In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).

Context: The McDonnell Aircraft Corporation was an American aerospace manufacturer based in St. Louis, Missouri. The company was founded on July 6, 1939 by James Smith McDonnell, and was best known for its military fighters, including the F-4 Phantom II, and manned spacecraft including the Mercury capsule and Gemini capsule. McDonnell Aircraft later merged with the Douglas Aircraft Company to form McDonnell Douglas in 1967., Aerospace is the human effort in science, engineering and business to fly in the atmosphere of Earth (aeronautics) and surrounding space (astronautics). Aerospace organisations research, design, manufacture, operate, or maintain aircraft and/or spacecraft. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications., A rotorcraft or rotary-wing aircraft is a heavier-than-air flying machine that uses lift generated by wings, called rotary wings or rotor blades, that revolve around a mast. Several rotor blades mounted on a single mast are referred to as a rotor. The International Civil Aviation Organization (ICAO) defines a rotorcraft as "supported in flight by the reactions of the air on one or more rotors". Rotorcraft generally include those aircraft where one or more rotors are required to provide lift throughout the entire flight, such as helicopters, cyclocopters, autogyros, and gyrodynes. Compound rotorcraft may also include additional thrust engines or propellers and static lifting surfaces., A rocket (from Italian "rocchetto" "bobbin") is a missile, spacecraft, aircraft or other vehicle that obtains thrust from a rocket engine. Rocket engine exhaust is formed entirely from propellant carried within the rocket before use. Rocket engines work by action and reaction and push rockets forward simply by expelling their exhaust in the opposite direction at high speed, and can therefore work in the vacuum of space., The Douglas Aircraft Company was an American aerospace manufacturer based in Southern California. It was founded in 1921 by Donald Wills Douglas, Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas. Douglas Aircraft Company largely operated as a division of McDonnell Douglas (MD) after the merger. MD later merged with Boeing in 1997., The Boeing Company is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, and satellites worldwide. The company also provides leasing and product support services. Boeing is among the largest global aircraft manufacturers; it is the second-largest defense contractor in the world based on 2015 revenue, and is the largest exporter in the United States by dollar value. Boeing stock is a component of the Dow Jones Industrial Average., Embraer S.A. is a Brazilian aerospace conglomerate that produces commercial, military, executive and agricultural aircraft and provides aeronautical services. It is headquartered in São José dos Campos, São Paulo State., McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it produced a number of well-known commercial and military aircraft such as the DC-10 airliner and F-15 Eagle air-superiority fighter., As of September 2015 , American Airlines operates a mainline fleet of 939 aircraft , making it the largest commercial fleet in the world . It primarily operates a mix of Airbus and Boeing ( including McDonnell Douglas ) narrow - body and wide - body aircraft , as well as one narrow - body variant from Embraer . American is currently in the process of the largest fleet renewal in its history , with over 300 aircraft on order from Airbus and Boeing . American Airlines also announced a new livery to be painted on all aircraft . American Airlines expects to be done repainting all aircraft by the end of 2017 ., An airplane or aeroplane (informally plane) is a powered, fixed-wing aircraft that is propelled forward by thrust from a jet engine or propeller. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectrum of uses for airplanes includes recreation, transportation of goods and people, military, and research. Commercial aviation is a massive industry involving the flying of tens of thousands of passengers daily on airliners. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled., Subject: american airlines fleet, Relation: item_operated, Options: (A) 4 (B) aircraft (C) airliner (D) spacecraft
airliner