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.

Example Input: Question: Which professional ice hockey league that McNab ever played in was formed first? Passage:After playing junior hockey in Saskatoon, Saskatchewan, McNab played on the Omaha Knights of the USHL in the 1946–48 season before being called up to the Detroit Red Wings of the National Hockey League in 1947. He would play on and off with the Red Wings until 1951, playing on the team that won the Stanley Cup in 1950. He played for the Indianapolis Capitols of the American Hockey League in 1950–51. Before the 1951–52 season, he was traded by the Red Wings to the Chicago Black Hawks, but never played for the team. Back surgery kept him out of action in 1951–52 and McNab then joined the New Westminster Royals of the Western Hockey League, where he played for seven seasons, retiring in 1959. He was voted league MVP in 1955, scoring 32 goals and 81 points.
 Links: a. Omaha Knights (AHA) b. Saskatoon c. National Hockey League d. United States Hockey League (1945–1951)
Example Output: d

Example Input: Question: Who was in charge at Princeton University the year Barschall graduated from that school? Passage:Barschall was born as Heinrich Hermann Barschall in Berlin, Germany; his father was a patent attorney who had received a Ph.D. in chemistry after studying with Nobel Laureates Emil Fischer and Fritz Haber. After beginning study in several universities in Germany, he emigrated to the United States in 1937 during the early Holocaust period; though raised as a Lutheran, he had some Jewish ancestry. He received his Ph.D. from Princeton University in 1940 under the direction of Rudolf Ladenburg; he also worked closely with John A. Wheeler. After a suggestion by Niels Bohr, he carried out in only a few days with fellow graduate student Morton H. Kanner the first demonstration of fission by fast neutrons and thorium and uranium. His thesis was on the interaction of fast neutrons with helium. In a paper with John A. Wheeler he reported the discovery of spin-orbit coupling in neutron scattering.
 Links: a. Emil Fischer b. Princeton University c. Jews d. John Archibald Wheeler
Example Output: b

Example Input: Question: How many children were part of the Hitler Youth the year the German Eastern Front collapsed? Passage:Spindler was born in Łódź, Poland, to an ethnic German family. He was the son of Gertrud Alma (née Bernewitz) and Oskar Karl Spindler; his father was a businessman. Spindler was considered part of the Volksdeutsche by the Nazi regime, and after the German invasion of Poland in 1939 was required to join the Deutsches Jungvolk (part of the Hitler Youth). When Germany's Eastern Front collapsed in 1944, Spindler and other children of Łódź were evacuated to a rural estate north of the city. In January 1945, he and his companions were forced to flee west on foot to escape the advancing Red Army; many of them were killed by starvation, exposure, or bombing raids. Spindler was eventually reunited with his family in Magdeburg, and they settled in Weißenfels, Saxony-Anhalt, which became part of the Soviet occupation zone and later East Germany. He was blacklisted from attending university due to his anti-Soviet views, and at the age of 17 was granted permission to move to Australia, sponsored by a relative who had settled in Melbourne.
 Links: a. Melbourne b. German minority in Poland c. Hitler Youth d. Red Army
Example Output:
c