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: Were the actor that played John Rollason and the actress that played his wife born in the same country? Passage:Dr. John Rollason (Peter Cushing), his wife, Helen (Maureen Connell), and assistant, Peter Fox (Richard Wattis), are guests of the Lama (Arnold Marle) of the monastery of Rong-buk while on a botanical expedition to the Himalayas. A second expedition, led by Dr. Tom Friend (Forrest Tucker) accompanied by trapper Ed Shelley (Robert Brown), photographer Andrew McNee (Michael Brill) and Sherpa guide Kusang (Wolfe Morris), arrives at the monastery in search of the legendary Yeti or Abominable Snowman. Rollason, despite the objections of his wife and the Lama, decides to join Friend's expedition. Whereas Rollason is motivated by scientific curiosity to learn more about the creature, Friend seeks fame and fortune and wants to capture a live Yeti and present it to the world's press.
Links: a. Botany b. Forrest Tucker c. Sherpa people d. Peter Cushing
Example Output: d

Example Input: Question: Which team that Lepage drove for after he left Ridling raced in NASCAR first? Passage:Lepage made his Busch Series debut in 1986 at Oxford Plains Speedway, starting 41st and finishing 15th in the No. 09 Buick owned by Carl Merrill. He became a Busch Series regular in 1994, serving as an owner/driver in the No. 71 Vermont Teddy Bear Company car and running for Rookie of the Year honors. He had a best finish of 9th at New Hampshire International Speedway, in which he got a flat tire at the very end of the race, and finished 24th in points. The 1995 season resulted in five Top 10s and finishing 18th in points. At the end of the season, he lost his sponsorship and ran his own car in 1996 unsponsored until April. Lepage then joined David Ridling and his No. 88 Ridling Motorsports team with sponsorship from Ridling's own Farmer's Choice Fertilizer. He won his first career race at the season finale Jiffy Lube Miami 300 with Hype Energy sponsorship. He finished eighth in points with 1 win, three Top 5s and 10 Top 10s. He ran most of the 1997 season driving for Ridling before leaving due to the team losing its sponsor. Lepage would finish out the year running for Phoenix Racing and ST Motorsports. He finished 12th in points, posting three Top 5s and six Top 10s. Lepage had his Cup debut by qualifying for the Fall Charlotte race in the No. 91 LJ Racing car in an impressive 12th. He would also run the Fall Talladega and Atlanta races with finishes of 17th at Talladega and 29th at Atlanta.
Links: a. Oxford Plains Speedway b. Phoenix Racing (NASCAR team) c. Ford EcoBoost 300 d. 1997 NASCAR Busch Series
Example Output: b

Example Input: Question: How old was Charlemagne's son when he destroyed the Ring of the Avars? Passage:Since about 560, the Avars had ruled over large parts of the Pannonian Basin and Carantania southeast of Francia, though in the last decades, the Avar Khaganate had to deal with Bulgarian and Croat incursions. To secure the frontier of his empire and the traffic on the trade routes to the east, Charlemagne allied with Khan Krum of Bulgaria and the Croatian duke Vojnomir, and from 791 launched several campaigns against the Avars, where he, according to the Vita Karoli Magni, encountered only modest opposition. In 796 Carolingian forces under Charlemagne's son Pepin of Italy destroyed the main Avar fortress called the Ring of the Avars and made the Khagan a Frankish vassal, while the remaining Avars retreated behind the Tisza River. The victory is perpetuated by the poem De Pippini regis Victoria Avarica.
Links: a. Francia b. Khagan c. First Bulgarian Empire d. Pepin of Italy
Example Output:
d