In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Let me give you an example: what is the first event mentioned?, Context: The Russian Revolution is the series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. Following the abdication of Nicholas II of Russia, the Russian Provisional Government was established. In October 1917, a red faction revolution occurred in which the Red Guard, armed groups of workers and deserting soldiers directed by the Bolshevik Party, seized control of Saint Petersburg (then known as Petrograd) and began an immediate armed takeover of cities and villages throughout the former Russian Empire.
The answer to this example can be: Russian Revolution
Here is why: This is a good example, and the Russian Revolution is the first event mentioned.

OK. solve this:
Which unit is a shorter distance between miles and kilometers?, Context: The "Big Five" game animals of Africa, that is the lion, leopard, buffalo, rhinoceros, and elephant, can be found in Kenya and in the Masai Mara in particular. A significant population of other wild animals, reptiles and birds can be found in the national parks and game reserves in the country. The annual animal migration occurs between June and September with millions of animals taking part, attracting valuable foreign tourism. Two million wildebeest migrate a distance of 2,900 kilometres (1,802 mi) from the Serengeti in neighbouring Tanzania to the Masai Mara in Kenya, in a constant clockwise fashion, searching for food and water supplies. This Serengeti Migration of the wildebeest is a curious spectacle listed among the 10 Natural Wonders of Africa.
Answer:
kilometres