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: What country did McGillivray return to before taking a trip to Scotland and England? Passage:McGillivray returned to Montreal in 1793 and then took a trip to Scotland and England. He was now a partner in McTavish, Frobisher & Co., who controlled the NWC. With John Gregory, he was sent to manage the company's huge depot at Grand Portage, stirring jealousy among some of the other partners. When Joseph Frobisher retired in 1798, McGillivray took his place. He set up an agency at New York City to get around the East India Company's monopoly enabling them to trade with China. He was closely involved too with the firm of McTavish, Fraser & Co., at London, managed by another relation of his uncle's, John Fraser. In 1803, he helped organize the move of the NWC's main depot from Grand Portage to Thunder Bay. All this time he was dealing with relations with the Hudson's Bay Company and the splinter XY Company that had broken away from the NWC, led by John Richardson.
 Links: a. Montreal b. Montreal c. North West Company d. New York City
Example Output: a

Example Input: Question: When was the man whose name is used as the unit of radio wave frequency born?  Passage:A modulated radio wave, carrying an information signal, occupies a range of frequencies. See diagram. The information (modulation) in a radio signal is usually concentrated in narrow frequency bands called sidebands (SB) just above and below the carrier frequency. The width in hertz of the frequency range that the radio signal occupies, the highest frequency minus the lowest frequency, is called its bandwidth (BW). A given amount of bandwidth can carry the same amount of information (data rate in bits per second) regardless of where in the radio frequency spectrum it is located, so bandwidth is a measure of information-carrying capacity. The bandwidth required by a radio transmission depends on the data rate of the information (modulation signal) being sent, and the spectral efficiency of the modulation method used; how much data it can transmit in each kilohertz of bandwidth. Different types of information signals carried by radio have different data rates. For example, a television (video) signal has a greater data rate than an audio signal.
 Links: a. Data signaling rate b. Carrier wave c. Hertz d. Audio signal
Example Output: c

Example Input: Question: Did Jackie Jensen win a World Series with the Boston Red Sox? Passage:Jack Eugene Jensen (March 9, 1927 – July 14, 1982) was an American right fielder in Major League Baseball who played for three American League (AL) teams from 1950 to 1961, most notably the Boston Red Sox. He was named the AL's Most Valuable Player (MVP) in after hitting 35 home runs and leading the league with 122 runs batted in (RBIs); he also led the league in RBIs two other years, and in triples and stolen bases once each. Respected for his throwing arm, he won a Gold Glove Award and led the AL in assists and double plays twice each. He retired in his early thirties as major-league baseball expanded westward, due to an intense fear of flying. After being a two-sport star in college, Jensen was the first man to play in the Rose Bowl, the World Series, and the MLB All-Star Game.
 Links: a. World Series b. Right fielder c. Boston Red Sox d. American League
Example Output:
a