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: How long had the Royal Canadian Air Force existed the year that the McDonnell CF-101 Voodoo began being operated by them? Passage:The McDonnell CF-101 Voodoo was an all-weather interceptor aircraft operated by the Royal Canadian Air Force and the Canadian Forces between 1961 and 1984. They were manufactured by the McDonnell Aircraft Corporation of St. Louis, Missouri for the United States Air Force (as F-101s), and later sold to Canada. CF-101s replaced the obsolete Avro CF-100 Canuck in the RCAF's all-weather fighter squadrons. The Voodoo's primary armament was nuclear AIR-2A Genie unguided air-to-air rockets, and there was significant political controversy in Canada about their adoption. Although they never fired a weapon in wartime, the CF-101 served as Canada's primary means of air defence from Quick Reaction Alert facilities at Canadian airbases. The CF-101s were retired in the 1980s and replaced with McDonnell Douglas CF-18 Hornet fighters. Many examples are preserved in museums and parks in Canada and the United States.
 Links: a. AIR-2 Genie b. Royal Canadian Air Force c. McDonnell Douglas CF-18 Hornet d. Royal Canadian Air Force
Example Output: b

Example Input: Question: When was Sale's first husband born? Passage:On June 21, 2012, Simpson married Canadian figure skater Jamie Salé, whom he had "known for years from the Edmonton skating scene". They had been paired as partners in late 2009 for the first season of the CBC show Battle of the Blades, which they won. Simpson and Salé have one daughter, Samantha Rae Simpson, born on July 7, 2013. Through this marriage, Simpson is also a stepfather to Salé's son Jesse Pelletier (born September 30, 2007), from her first marriage to skating partner David Pelletier. He also has three children from a previous marriage, including son Dillon, who was drafted by the Edmonton Oilers in the 4th round of the 2011 NHL Entry Draft and is currently a defenseman for the Bakersfield Condors.
 Links: a. Battle of the Blades b. David Pelletier c. Battle of the Blades (season 1) d. Stepfather
Example Output: b

Example Input: Question: What was Daniel Coit Gilman president of? Passage:In his will Johns Hopkins (1795-1873) left his summer home and estate, Clifton, then northeast of Baltimore, off the Harford Road, to the university for its new campus along with $7 million, split between the university and a hospital, also named for him. One of his provisions was that only interest obtained from his stock in the Baltimore and Ohio Railroad could be used to build facilities for the university. Unfortunately, after Johns Hopkins' death, the B&O Railroad fell into mismanagement; its eventual financial collapse was hastened by the Financial Panic and Recession of 1893 and the stock's value declined drastically. Therefore, the original campus of the university was established by first President Daniel Coit Gilman in downtown Baltimore along North Howard Street, between West Center, Little Ross, and West Monument Streets on the west side of the Mount Vernon-Belvedere neighborhood, where buildings were already available. However, this location did not permit room for growth and soon the trustees began to look for a place to move. Eventually, Hopkins would relocate to the former Homewood House and Estate of Charles Carroll, Jr. (son of Charles Carroll of Carrollton, 1737-1832) built 1801-1803, and the later Wyman Villa estate of JHU Board member William Wyman, built in the 1880s. Here JHU created the park-like main campus of Hopkins Homewood, set on 140 acres (0.57 km²) in what today lies between the north Baltimore neighborhoods of Charles Village (begun in the 1870s, and then known as Peabody Heights) to the east, the planned suburban-style communities of Guilford (established 1913) and Roland Park (established early 1890s) to the north, and to the west, the mill towns of Hampden-Woodberry along the Jones Falls stream valleys and tributary Stony Run through Wyman Park and the Wyman Park Dell.
 Links: a. Roland Park, Baltimore b. Panic of 1893 c. Guilford, Baltimore d. Daniel Coit Gilman
Example Output:
d