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 age bracket plays for the Real Madrid's youth system? Passage:Casillas began his career in Real Madrid's youth system, known as La Fábrica, during the 1990–91 season. On 27 November 1997, at age 16 and still a junior, he was first called up to the senior team squad to face Rosenborg in the UEFA Champions League, although he remained on the bench throughout. After spending a season with the C-team in the fourth tier, during which they won their regional group, he came into contention as the club's first-choice between the posts. In starting the 1999–2000 UEFA Champions League group stage fixture against Olympiakos on 15 September 1999, he became the youngest goalkeeper ever to feature in the competition at the time, aged 18 years and 177 days; a record which was only broken in October 2017 by Mile Svilar. Three days earlier, Casillas had made his La Liga debut in a 2–2 draw against Athletic Bilbao at San Mamés Stadium. In May 2000, he became the youngest ever goalkeeper to play in and win a Champions League final when Real Madrid defeated Valencia 3–0, just four days after his 19th birthday.
 Links: a. Olympiacos F.C. b. Real Madrid CF (youth) c. La Fábrica d. Real Madrid CF (youth)
Example Output: b

Example Input: Question: How long is the fault that lies to the east of Ice Mountain? Passage:Ice Mountain is an arc-shaped forested ridge of the Allegheny Mountains, part of the Ridge-and-valley Appalachians. It is above mean sea level at its summit. Ice Mountain is a large mass of Devonian Oriskany (Ridgeley) sandstone and Marcellus shale with numerous bare rock slopes and vertical cliffs. Ice Mountain lies on the west side of the Timber Mountain anticline and to the west of North Mountain fault, which places it on the Martinsburg allochthonous sheet. Ice Mountain is situated along North River and is known for the several hundred yards of ice that form at its base all year long. At its southern end overlooking the community of North River Mills is located Raven Rocks, a set of stone chimney outcrops. Raven Rocks is in height above mean sea level with vertical cliffs measuring nearly in height. Raven Rocks were named because of the presence of ravens during pioneer days. The present Raven Rocks is the remaining vestige of a once towering cliff that overlooked the North River. Geologically, Ice Mountain is a northern extension of North River Mountain.
 Links: a. Anticline b. Fault (geology) c. North Mountain (Virginia-West Virginia) d. Outcrop
Example Output: c

Example Input: Question: What city is the team in that Kansas beat in the second round of the 2011 NCAA tournament? Passage:The 2010–11 Kansas Jayhawks men's basketball team represented the University of Kansas in the 2010–11 NCAA Division I men's basketball season, which was the Jayhawks' 113th basketball season. The head coach was Bill Self, who was serving his 8th year. The team played its home games in Allen Fieldhouse in Lawrence, Kansas and are members of the Big 12 Conference. They finished the season 35–3, 14–2 in Big 12 play to claim the regular season conference title. They were also champions of the 2011 Big 12 Men's Basketball Tournament. They earned a #1 seed in the Southwest Region in the 2011 NCAA Men's Division I Basketball Tournament where they defeated Boston University in the second round and Illinois in the third round to advance to the Sweet Sixteen. They defeated Richmond to advance to the Elite Eight where they were upset by Virginia Commonwealth.
 Links: a. Allen Fieldhouse b. Allen Fieldhouse c. 2010–11 Illinois Fighting Illini men's basketball team d. Boston University Terriers
Example Output:
c