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 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: Which episode with Malohkeh had the highest ratings? Passage:Chibnall suggested including a "bonkers" gang of characters picked from around time and space. He felt that Doctor Who could have "collisions of characters that no other show in the world can do", and that it was about finding a "disparate" group of characters who would "bounce" off each other. Nefertiti's decision not to return to her own time fits in with the historical record, as the date and cause of her death are unknown. Chibnall asked to introduce Rory's father, as Amy and Rory would be leaving in four episodes and Rory's family life had not been explored yet. Mark Williams who played Rory's father previously appeared in the Fifth Doctor audio adventure The Eternal Summer. Rupert Graves, who played an Edwardian hunter in this episode, previously worked with Moffat on the BBC series Sherlock. David Bradley's character, Solomon, was modelled on a "well-known nightclub owner with long hair". Chibnall described him as "half businessman, half Somali pirate". Bradley and Williams had previously worked together on the Harry Potter film franchise. Bradley was later cast as the First Doctor William Hartnell for the 50th anniversary documentary drama An Adventure in Space and Time. Comedy duo Mitchell and Webb provided the voices of Solomon's two robots; executive producer Caroline Skinner called the casting choice "perfect". Richard Hope, who played the Silurian Bleytal, previously appeared as Malohkeh in the episodes "The Hungry Earth", "Cold Blood" and "The Wedding of River Song".
Links: a. Richard Hope (actor) b. The Hungry Earth c. Mitchell and Webb d. Harry Potter (film series)
Example Output: b

Example Input: Question: Was Trudeau a member of the democratic socailist Cooperative Commonwealth Federation when he legalized homosexuality? Passage:Many young people in Canada at this time, especially young women, were influenced by the 1960s counterculture and identified with Trudeau, an energetic nonconformist who was relatively young. They were dazzled by his "charm and good looks", and a large fan base was established throughout the country. He would often be stopped in the streets for his autograph or for photographs. Trudeau had once sympathized with Marxists and had spent time in the democratic socialist Cooperative Commonwealth Federation, and many of his fans were attracted to his culturally liberal stances (he legalized homosexuality and created more flexible divorce laws as Justice Minister under Lester B. Pearson). Trudeau was also admired for his laid-back attitude and his celebrity relationships; in that word's prevailing use at the time, describing a modern, "hip and happening person", he was often described as a swinger. A high point happened during Trudeau's election campaign in 1968 during the annual Saint-Jean-Baptiste Day parade in Montreal, when rioting Quebec separatists threw rocks and bottles at the grandstand where Trudeau was seated. Rejecting the pleas of his aides that he take cover, Trudeau stayed in his seat, facing the rioters, without any sign of fear. The image of the politician showing such courage impressed the Canadian people, and he handily won the election the next day.
Links: a. Quebec sovereignty movement b. Co-operative Commonwealth Federation c. Canada d. Quebec sovereignty movement
Example Output:
b