In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Input: Consider Input: Question: How wide is the body of water that separates the Eurasian and North American continents? Passage:The Russian Empire began its interest of the Pacific Northwest in the 18th century, initially curious if there was a land connection between the Eurasian and North American Continents. Two expeditions were led by Vitus Bering, with the findings proving the separation of two continents through the Bering Sea. Being the first European nation to chart much of what comprises the modern American state of Alaska, many locations retain Russian place names. The discovery of sizable fur bearing populations by Bering drew the attention of promyshlenniki previously engaged in the Siberian fur trade. Based out of the Siberian ports of Okhotsk or Petropavlovsk, fur trappers sailed and reported the location of land formations like the Aleutian Islands, Kodiak Island and portions of the Alaskan mainland. Relations with Native Alaskans was often terse due to the uncontrolled actions of particular promyshlenniki who killed and raped Indigenous on islands they trapped furs.
 Links: a. Bering Sea b. Siberia c. Russian Empire d. Bering Sea

Output: a


Input: Consider Input: Question: When did the Tokyo Kaisei school change it's name? Passage:The Japanese exhibition at the fair was the product of years of preparation. The empire had received its invitation in 1871, close on the heels of the Meiji Restoration, and a government bureau was established to produce an appropriate response. Shigenobu Okuma, Tsunetami Sano, and its other officials were keen to use the event to raise the international standing of Japanese manufactures and boost exports. 24 engineers were also sent with its delegation to study cutting-edge Western engineering at the fair for use in Japanese industry. Art and cultural relics at the exhibit were verified by the Jinshin Survey, a months-long inspection tour of various imperial, noble, and temple holdings around the country. The most important products of each province were listed and two specimens of each were collected, one for display in Vienna and the other for preservation and display within Japan. Large-scale preparatory exhibitions with this second set of objects were conducted within Japan at the Tokyo Kaisei School (today the University of Tokyo) in 1871 and at the capital's Confucian Temple in 1872; they eventually formed the core collection of the institution that became the Tokyo National Museum. 
 Links: a. University of Tokyo b. Sano Tsunetami c. Ōkuma Shigenobu d. University of Tokyo

Output: a


Input: Consider Input: Question: Who replaced Vandenberg as Vice Commander in Chief of the Pacific Air Forces? Passage:Vandenberg graduated from the United States Military Academy in 1951 (where Buzz Aldrin was one of his classmates). In 1953, Vandenberg was assigned to the 86th Fighter-Bomber Wing. Later he would serve as a flight commander with the 413th Tactical Fighter Wing and the 31st Tactical Fighter Wing. He graduated from the Air Command and Staff College in 1961, after which he was assigned to the 4th Tactical Fighter Wing. In 1963, Vandenberg was appointed Operations Officer with the 23rd Tactical Fighter Squadron. During the Vietnam War, Vandenberg commanded the 390th Tactical Fighter Squadron. Upon returning stateside he was assigned to The Pentagon to work in the Office of the Director of Plans. He would graduate from the National War College in 1969 and return to The Pentagon to work with the Joint Chiefs of Staff. In 1971, Vandenberg became commander of the 12th Flying Training Wing. Vandenberg was named Vice Commandant of Cadets at the United States Air Force Academy in 1972. He would serve as Commandant from 1973 to 1975, during which time he assumed the rank of brigadier general. From 1976 to 1979, Vandenberg served at Headquarters U.S. Air Force, first as Deputy Director of Plans, later as Director of Operations and Readiness, and finally as Assistant Deputy Chief of Staff for Operations, Plans, and Readiness. Vandenberg was ultimately named Vice Commander in Chief of the Pacific Air Forces. His retirement was effective as of January 1, 1981.
 Links: a. Buzz Aldrin b. Pacific Air Forces c. 4th Fighter Wing d. Air Command and Staff College


Output: b