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.

Input: Consider Input: Question: How many miles long is the river that Silvanus drove the Alamanni tribesmen back from? Passage:Silvanus was born in Gaul, the son of Bonitus, a Laetic Frankish general who had supported Constantine I in the civil war against Licinius. Like so many other Franks of his times, and like his father before him, he was a loyal and thoroughly romanized "barbarian" in the military service of the Empire. By AD 351, he held the rank of tribune and was one of the senior officers who defected to Emperor Constantius II at the Battle of Mursa Major, after initially supporting the usurper Magnentius. An able soldier, Silvanus was eventually promoted to the rank of Magister militum per Gallias, a crucial post, then in AD 352-353, Constantius personally entrusted him with the difficult task of driving the Alamanni tribesmen raiding and looting in Gaul back beyond the Rhine, and restoring the fast eroding Roman authority in the province. This Silvanus fulfilled partly by bribing the Alamanni chieftains with the taxes he had collected, partly by defeating the Alamanni in battle and partly by suppressing the local bagaudae insurrections flaring up again in central and northern Gaul.
 Links: a. Bonitus (magister militum) b. Constantine the Great c. Rhine d. Rhine

Output: c


Input: Consider Input: Question: Which of the two companies that posted previews  of Somebody to Love was founded first? Passage:A preview of the video was posted on AOL's PopEater.com, and subsequently on Bieber's VEVO channel, including behind the scenes clips of Bieber with the dancers, and highlights of the video with Usher and in front of a green screen. Bieber said, "It's really awesome to be able to work with professional dancers, you know, people that were in, like, ABDC, and also got an approval from choreographer Jamaica, who said Bieber was "killing it" and that she didn't have to give him any corrections. It made its premiere during the June 17, 2010 results show of the seventh season of So You Think You Can Dance, and was introduced by Usher after his performance of "OMG". It later premiered that night on VEVO and on June 18, 2010 on 20/20at the end of their show. The video features dance crews including, America's Best Dance Crew season 5 winners Poreotics, and Season 3's runner up Beat Freaks, as well as The Syrenz, LXD, Medea Sirkas, solo acts Simrin Player and Bboy Fly, and other dancers and crews. Singer/actress and model Katerina Graham makes a cameo in a scene with Poreotics. Bieber's best friend Ryan Butler, who appeared in the "One Time" video, also appears alongside Bieber, wearing a T-shirt advertising his Twitter account. According to Tamar Antai of MTV News the video "makes vague allusions" to clips for Busta Rhymes' "Pass the Courvoisier, Part II" and Chris Brown's "Wall to Wall". A backpack choreography scene with LXD recalls Usher's 1997 video for "You Make Me Wanna".
 Links: a. AOL b. 20/20 (American TV program) c. MTV News d. One Time (Justin Bieber song)

Output: a


Input: Consider Input: Question: Which team won more games the year Cowan started with the Rams, the Vikings or the Cowboys? Passage:Charles Edward Cowan (June 19, 1938 in Braeholm, West Virginia – April 29, 1998 in Los Angeles, California) was an American football offensive tackle who played fifteen seasons in the National Football League with the Los Angeles Rams from 1961 to 1975. Cowan was a huge intimidating presence on the left of Tom Mack, a member of the Pro Football Hall of Fame, from 1966 to 1975, forming a potent left side of the offensive line, with help from Ken Iman at center from 1965 to 1975. In that 1961 to 1975 span, the Rams made the playoffs 5 times (1967,1969,1973,1974,1975), reaching the NFC championship game of the 1974-75 NFL playoffs and the 1975-76 NFL playoffs, but losing to the Minnesota Vikings and to the Dallas Cowboys, respectively. In the 1974 divisional round, the Rams defeated the Washington Redskins, as Cowan was successful against the opposing the right defensive end Verlon Biggs. In the 1975 divisional round, Doug France started in his place as the Rams defeated the St. Louis Cardinals. Cowan came back to play against the Cowboys, his final game, as the Rams could not get past them. Cowan was replaced by Doug France in 1976.
 Links: a. Minnesota Vikings b. Doug France c. Dallas Cowboys d. St. Louis Cardinals


Output: c