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

Ex Input:
Besides sheriffs and posses, who helped keep the peace?, Context: In the American Old West, policing was often of very poor quality.[citation needed] The Army often provided some policing alongside poorly resourced sheriffs and temporarily organized posses.[citation needed] Public organizations were supplemented by private contractors, notably the Pinkerton National Detective Agency, which was hired by individuals, businessmen, local governments and the federal government. At its height, the Pinkerton Agency's numbers exceeded those of the United States Army.[citation needed]

Ex Output:
Army

Ex Input:
What is Rayleigh scattering?, Context: In nature, the red color of blood comes from hemoglobin, the iron-containing protein found in the red blood cells of all vertebrates. The red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. It also causes the red color of the planet Mars. The red sky at sunset and sunrise is caused by an optical effect known as Rayleigh scattering, which, when the sun is low or below the horizon, increases the red-wavelength light that reaches the eye. The color of autumn leaves is caused by pigments called anthocyanins, which are produced towards the end of summer, when the green chlorophyll is no longer produced. One to two percent of the human population has red hair; the color is produced by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin.

Ex Output:
optical effect

Ex Input:
Which is not a last name, MacArthur or Bonus?, Context: His primary duty was planning for the next war, which proved most difficult in the midst of the Great Depression. He then was posted as chief military aide to General MacArthur, Army Chief of Staff. In 1932, he participated in the clearing of the Bonus March encampment in Washington, D.C. Although he was against the actions taken against the veterans and strongly advised MacArthur against taking a public role in it, he later wrote the Army's official incident report, endorsing MacArthur's conduct.

Ex Output:
Bonus