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: On what date did Apollo 11 land at it's destination site? Passage: are three views of Mare Tranquillitatis on the Moon, taken by the mapping camera of the Apollo 17 mission in 1972, facing south-southwest from an average altitude of 111 km on Revolution 36 of the mission. At the left is the east side of Mare Tranquillitatis, with the craters Franz (bottom right), Lyell (dark floor, right of center), and Taruntius (upper left). The "bay" of dark mare (basalt) at left is Sinus Concordiae, with "islands" of older, light highland material. At the right is the crater Cauchy, which lies between the Rupes Cauchy and Cauchy rille. The center photo shows the central mare with craters Vitruvius (lower right) and Gardner (bottom center). At the horizon are lighter highlands at the southern margin of the mare, near the Apollo 11 landing site. The crater Jansen is visible at the edges of both the center and right photos. The right photo shows the western mare, with the craters Dawes (lower left) and the large Plinius (43 km diameter), with the Plinius Rilles in the foreground. These photos were taken within minutes of each other as the command module America orbited the Moon. The Sun elevation drops from 46 degrees at left to 30 degrees at right.
 Links: a. Apollo 11 b. Apollo 17 c. Lyell (lunar crater) d. Plinius (crater)
Example Output: a

Example Input: Question: Did the operation that Musicki contacted the Chetnik leader about actually take place? Passage:Mušicki was stationed in Slavonski Brod at the time of the Axis invasion of Yugoslavia in April 1941 and served as the Royal Yugoslav Army commander responsible for the railroad between Belgrade and Zagreb in the rank of colonel. He demonstrated his support for the Germans by helping their forces during the invasion. Yugoslavia was quickly conquered by the Axis powers and Mušicki remained in Slavonski Brod for several months after the conquest. He attempted to join the Ustaše Militia there, but was rejected. He went to Belgrade in mid-August, where he was received by Zbor leader Dimitrije Ljotić. On 6 October, Milan Nedić, the Prime Minister of the Axis-installed puppet Government of National Salvation, appointed Mušicki to lead the Serbian Volunteer Command (, SDK). Mušicki was involved in executing Serb civilians in the town of Čačak in December 1941. He and Milan Aćimović contacted Chetnik leader Draža Mihailović on 5 December, possibly in an effort to warn him in advance of the assault the Germans had planned, codenamed Operation Mihailovic. This action prompted the Germans to question Mušicki's loyalty. He was removed from command at the end of 1941 and imprisoned by the Germans, but was later freed at Nedić's intervention.
 Links: a. Royal Yugoslav Army b. Operation Mihailovic c. Dimitrije Ljotić d. Government of National Salvation
Example Output: b

Example Input: Question: How many matches did Nakagawa play for the Yokohama Marinos in 1996? Passage:Nakagawa was born in Osaka Prefecture on August 26, 1969. After graduating from Kokushikan University, he joined Yokohama Flügels in 1992. However he could hardly play in the match behind Atsuhiko Mori. In June 1995, he moved to rival club in Yokohama, Yokohama Marinos. In 1996, he played many matches when regular goalkeeper Yoshikatsu Kawaguchi let the club for 1996 Summer Olympics and injury. In 1998, he moved to Kyoto Purple Sanga. However he could hardly play in the match behind Shigetatsu Matsunaga. In March 2000, he moved to Nagoya Grampus Eight on loan. In 2001, he returned to Purple Sanga was relegated to J2 League. From June, he became a regular goalkeeper and the club returned to J1 League in a season. However he could hardly play in the match in 2002 season and retired end of 2002 season.
 Links: a. Atsuhiko Mori b. Football at the 1996 Summer Olympics c. Yoshikatsu Kawaguchi d. Yokohama F. Marinos
Example Output:
d