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: In 1958 did the Linguistic Society of America have more total members than the American Philosophical Society? Passage:He was educated in the German Gymnasium, where he learned the classical languages, and trained as an Indo-Europeanist and a historical and comparative linguist in universities in Munich, Zurich, Padua, and Florence. His refugee status compelled these moves (his grandparents were Jewish, and by 1933 Jews were forbidden to attend German universities). In 1939 he escaped to the United States, where he was at first a research assistant at Yale. He taught at the University of Pennsylvania from 1948 until his retirement in 1985. He was a member of the Linguistic Society of America, of which he was elected President in 1958, and a member of the American Philosophical Society for more than 30 years. He was elected to the National Academy of Sciences. He spent a year at Oxford in 1976 and was elected a Corresponding Fellow of the British Academy in 1986.
 Links: a. Indo-European studies b. Historical linguistics c. Historical linguistics d. American Philosophical Society
Example Output: d

Example 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
Example Output: a

Example Input: Question: What year was the battle of the Gap? Passage:After the D-Day invasion, was reassigned to IX Tactical Air Command (IX TAC) and directed to provide ground support for advancing United States First Army forces in France, attacking enemy targets initially in the Cotentin Peninsula, then supported Operation Cobra, the breakout of Normandy and attacked enemy forces in the Falaise-Argentan Gap. Wing headquarters and subordinate units operated primarily from liberated airfields and newly built temporary Advanced Landing Grounds in France, moved into north-central France, its groups attacking enemy targets near Paris then north-west into Belgium and the southern Netherlands. In December 1944/January 1945, engaged enemy targets on the north side of the Battle of the Bulge, then moved eastward into the Northern Rhineland as part of the Western Allied invasion of Germany.
 Links: a. Falaise Pocket b. Falaise Pocket c. Paris d. Normandy landings
Example Output:
a