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

[EX Q]: Who did Villa negotiate with to end his rebellion?, Context: Villa and Carranza had different political goals causing Villa to become an enemy of Carranza. After Carranza took control in 1914, Villa and other revolutionaries who opposed him met at what was called the Convention of Aguascalientes. The convention deposed Carranza in favor of Eulalio Gutiérrez. In the winter of 1914 Villa's and Zapata's troops entered and occupied Mexico City. Villa was forced from the city in early 1915 and attacked the forces of Gen. Obregón at the Battle of Celaya and was badly defeated in the bloodiest battle of the revolution, with thousands dead. With the defeat of Villa, Carranza seized power. A short time later the United States recognized Carranza as president of Mexico. Even though Villa's forces were badly depleted by his loss at Celaya, he continued his fight against the Carranza government. Finally, in 1920, Obregón—who had defeated him at Celaya—finally reached an agreement with Villa end his rebellion.
[EX A]: Obregón

[EX Q]: Why did farmers have to leave?, Context: During the 1930s, parts of the state began suffering the consequences of poor farming practices, extended drought and high winds. Known as the Dust Bowl, areas of Kansas, Texas, New Mexico and northwestern Oklahoma were hampered by long periods of little rainfall and abnormally high temperatures, sending thousands of farmers into poverty and forcing them to relocate to more fertile areas of the western United States. Over a twenty-year period ending in 1950, the state saw its only historical decline in population, dropping 6.9 percent as impoverished families migrated out of the state after the Dust Bowl.
[EX A]: the consequences of poor farming practices, extended drought and high winds

[EX Q]: What is used as ammo?, Context: Bell is also credited with developing one of the early versions of a metal detector in 1881. The device was quickly put together in an attempt to find the bullet in the body of U.S. President James Garfield. According to some accounts, the metal detector worked flawlessly in tests but did not find the assassin's bullet partly because the metal bed frame on which the President was lying disturbed the instrument, resulting in static. The president's surgeons, who were skeptical of the device, ignored Bell's requests to move the president to a bed not fitted with metal springs. Alternatively, although Bell had detected a slight sound on his first test, the bullet may have been lodged too deeply to be detected by the crude apparatus.
[EX A]:
bullet