Given the question: Information:  - A cay (or ), also spelled caye or key, is a small, low-elevation, sandy island on the surface of a coral reef. Cays occur in tropical environments throughout the Pacific, Atlantic and Indian Oceans (including in the Caribbean and on the Great Barrier Reef and Belize Barrier Reef).  - The River Thames is a river that flows through southern England. At , it is the longest river entirely in England and the second longest in the United Kingdom, after the River Severn. It also flows through Oxford (where it is called Isis), Reading, Henley-on-Thames and Windsor. The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. It rises at Thames Head in Gloucestershire, and flows into the North Sea via the Thames Estuary. The Thames drains the whole of Greater London.   - Berkshire (or , abbreviated Berks) is a county in south east England, west of London. It was recognised as the Royal County of Berkshire because of the presence of Windsor Castle by the Queen in 1957 and letters patent issued in 1974. Berkshire is a county of historic origin and is a home county, a ceremonial county and a non-metropolitan county without a county council. Berkshire County Council was the main county governance from 1889 to 1998 except for the separately administered County Borough of Reading.  - A continent is one of several very large landmasses on Earth. Generally identified by convention rather than any strict criteria, up to seven regions are commonly regarded as continents. Ordered from largest in size to smallest, they are: Asia, Africa, North America, South America, Antarctica, Europe, and Australia. In geology, areas of continental crust include regions covered with water.  - Water is a transparent and nearly colorless chemical substance that is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is HO, meaning that its molecule contains one oxygen and two hydrogen atoms, that are connected by covalent bonds. Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure; but it often refers also to its solid state (ice) or its gaseous state (steam or water vapor). It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, and atmospheric humidity.  - Eton Wick is a village currently in the English ceremonial county of Berkshire, but traditionally in Buckinghamshire, on the River Thames. According to the Grid Ref at the 2011 Census the population was included in the civil parish of Eton. It is very close to both the historic towns of Windsor and Eton, as well as Slough and Dorney Lake, the rowing venue for the 2012 Summer Olympics. The village has grown rapidly between the 1880s and the 2000s.  - The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, it includes the island of Great Britain (the name of which is also loosely applied to the whole country), the north-eastern part of the island of Ireland, and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another sovereign statethe Republic of Ireland. Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-south-west, giving it the 12th-longest coastline in the world. The Irish Sea lies between Great Britain and Ireland. With an area of , the UK is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants. Together, this makes it the fourth most densely populated country in the European Union.  - Windsor is a historic market town and unparished area in the Royal Borough of Windsor and Maidenhead in Berkshire, England. It is widely known as the site of Windsor Castle, one of the official residences of the British Royal Family.  - Bush Ait is an island of Clewer , Berkshire in the Thames on the reach above Boveney Lock at the mouth of the Clewer Mill Stream which leads to Windsor Racecourse Marina . The island is unpopulated and wooded .  - Lake Island is an island on the coast of the Canadian province of British Columbia. It is located between Mathieson Channel and Lady Trutch Passage, and is flanked by Dowager Island (to the northwest), Lady Douglas Island (to the west), and a long finger shaped peninsula of the Canadian mainland to the east. Ironically, Lake Island is not a lake island, as it is in an inlet of the Pacific Ocean, and lies only some 6 kilometres from the open sea.  - The Thames Navigation Commission used to manage the River Thames in southern England. In particular, they were responsible for installing or renovating many of the locks on the river in the 18th and early 19th centuries  - Clewer Mill Stream is a narrow twisting backwater of the River Thames near Windsor, Berkshire, England, which leaves the main river at Bush Ait and rejoins just above Queen Elizabeth Bridge. It is about 1.5 miles long. Clewer Mill Stream is named after the watermill that it once drove.  - River Island is a London-headquartered high street fashion brand, which operates in a number of worldwide markets. Set up in 1948 by Bernard Lewis and his brothers in London, it is to this day still a private company owned by the Lewis family.  - Windsor Racecourse, also known as Royal Windsor Racecourse, is a thoroughbred horse racing venue located in Windsor, Berkshire, England. It is one of only two figure-of-eight courses in the United Kingdom, the other being at Fontwell Park.   - Boveney Lock is a lock on the River Thames situated on the Buckinghamshire bank opposite the Windsor Racecourse and close to Eton Wick. Boveney is a village a little way upstream on the same side. The lock was first built in 1838 by the Thames Navigation Commission. The lock was rebuilt in 1898 closer to the Buckinghamshire bank, and a set of boat rollers were installed on the old site.   - Buckinghamshire (or ), abbreviated Bucks, is a county in South East England which borders Greater London to the south east, Berkshire to the south, Oxfordshire to the west, Northamptonshire to the north, Bedfordshire to the north east and Hertfordshire to the east.  - Boveney is a village in Buckinghamshire, England, near Windsor.  - An ait (pronounced , like "eight") or eyot (pronounced , , or ) is a small island. It is especially used to refer to river islands found on the River Thames and its tributaries in England.  - Clewer (also known as Clewer Village) is an ecclesiastical parish and an area of Windsor in the county of Berkshire, England. Clewer makes up three wards of the Royal Borough of Windsor and Maidenhead, namely Clewer North, Clewer South and Clewer East.  - An archipelago, sometimes called an island group or island chain, is a chain, cluster or collection of islands. The word "archipelago" is derived from the Greek "-  arkhi-" ("chief") and "  pélagos" ("sea") through the Italian "arcipelago". In Italian, possibly following a tradition of antiquity, the Archipelago (from medieval Greek "*" and Latin "archipelagus") was the proper name for the Aegean Sea and, later, usage shifted to refer to the Aegean Islands (since the sea is remarkable for its large number of islands). It is now used to refer to any island group or, sometimes, to a sea containing a small number of scattered islands.  - An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island in a river or a lake island may be called an eyot or ait, and a small island off the coast may be called a holm. A grouping of geographically or geologically related islands is called an archipelago, e.g. the Philippines.  - The Philippines, officially the Republic of the Philippines, is a sovereign island country in Southeast Asia situated in the western Pacific Ocean. It consists of about 7,641 islands that are categorized broadly under three main geographical divisions from north to south: Luzon, Visayas, and Mindanao. The capital city of the Philippines is Manila and the most populous city is Quezon City, both part of Metro Manila. Bounded by the South China Sea on the west, the Philippine Sea on the east and the Celebes Sea on the southwest, the Philippines shares maritime borders with Taiwan to the north, Vietnam to the west, Palau to the east and Malaysia and Indonesia to the south.  - England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west. The Irish Sea lies northwest of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east and the English Channel to the south. The country covers five-eighths of the island of Great Britain (which lies in the North Atlantic) in its centre and south; and includes over 100 smaller islands such as the Isles of Scilly, and the Isle of Wight.    After reading the paragraphs above, choose the best answer for the entity that related to 'bush ait' with the relationship of 'located on terrain feature'.  Choices: - aegean sea  - africa  - asia  - british columbia  - caribbean  - coast  - earth  - england  - english channel  - europe  - great britain  - ireland  - irish sea  - london  - mainland  - mindanao  - pacific ocean  - river thames  - south america  - south china sea  - western europe
The answer is:
river thames