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.

Ex 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

Ex Output:
c


Ex Input:
Question: Which team won the Rose Bowl the year that Vols lost the Orange Bowl? Passage:The 1997 Tennessee Volunteers football team represented the University of Tennessee during the 1997 NCAA Division I-A football season. Quarterback Peyton Manning had already completed his degree in three years, and had been projected to be the top overall pick in the 1997 NFL Draft, but returned to Tennessee for his senior year. The Volunteers opened the season with victories against Texas Tech and UCLA, but for the third time in his career, Manning fell to Florida, 33–20. The Vols won the rest of their regular season games, finishing 10–1, and advanced to the SEC Championship Game against Auburn. Down 20–7, Manning led the Vols to a 30–29 victory. Throwing for four touchdowns, he was named the game's MVP, but injured himself in the process. The #3 Vols were matched up with #2 Nebraska in the Orange Bowl. Had Tennessee won and top-ranked Michigan lost to Washington State in the Rose Bowl, the Vols would have been expected to win the national championship. However, the Vols' defense could not stop Nebraska's rushing attack, giving up more than 400 yards on the ground in a 42–17 loss. As a senior, Manning won numerous awards. He was a consensus first-team All-American and won the Maxwell Award, the Davey O'Brien Award, the Johnny Unitas Award, and the Best College Football Player ESPY Award, among others. However, he did not win the Heisman Trophy, finishing runner-up to Charles Woodson, a CB from Michigan, and the only defensive player ever to win the Heisman Trophy.
 Links: a. 1997 Florida Gators football team b. 1997 Washington State Cougars football team c. 1997 Nebraska Cornhuskers football team d. 1997 Michigan Wolverines football team

Ex Output:
d


Ex Input:
Question: Who declared the Soviet Republic a socialist state during the October Revolution? Passage:The Russian Soviet Republic was proclaimed on 7 November 1917 (October Revolution) as a sovereign state and the world's first constitutionally socialist state with the ideology of Communism. The first Constitution was adopted in 1918. In 1922, the Russian SFSR signed the Treaty on the Creation of the USSR officially setting up of the Union of Soviet Socialist Republics. The 1977 Soviet Constitution stated that "[a] Union Republic is a sovereign [...] state that has united [...] in the Union" and "each Union Republic shall retain the right freely to secede from the USSR". On 12 June 1990, the Congress of People's Deputies adopted the Declaration of State Sovereignty, established separation of powers (instead of Soviet form of government), established citizenship of Russia and stated that the RSFSR shall retain the right of free secession from the USSR. On 12 June 1991, Boris Yeltsin (1931–2007), supported by the Democratic Russia pro-reform movement, was elected the first and only President of the RSFSR, a post that would later become the presidency of the Russian Federation.
 Links: a. Socialist state b. President of Russia c. Socialist state d. Boris Yeltsin

Ex Output:

a