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 after the construction of the cathedral where Rachel Treweek became the 41st Bishop was she installed there? Passage:On 26 March 2015, it was announced that Treweek was to become the next Bishop of Gloucester, the diocesan bishop of the Diocese of Gloucester. Though there had been two women appointed bishops previously in the Church of England, she was the first woman to be appointed a diocesan bishop, rather than as a suffragan bishop. She was the first woman to become a bishop in the Province of Canterbury, jointly with Sarah Mullally, Bishop of Crediton. On 15 June 2015, her election was confirmed during a sitting of the Arches Court of Canterbury at St Mary-le-Bow, City of London. At this point, she legally became the Bishop of Gloucester. On 22 July 2015, she was consecrated a bishop by Justin Welby, the Archbishop of Canterbury, during a ceremony at Canterbury Cathedral. She and Sarah Mullally (later Bishop of London) were the first women to be ordained as bishops at Canterbury Cathedral. On 19 September, she was installed at Gloucester Cathedral as the 41st Bishop of Gloucester.
 Links: a. Gloucester Cathedral b. Gloucester Cathedral c. Province of Canterbury d. Diocesan bishop
Example Output: a

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: Of the two indicator species of trees for the lower montane forest, which grows taller? Passage:Beginning near the elevation, the hot, dry summers and cool, moist winters of the Mediterranean climate give rise to the lower montane forest zone. This zone is also known as the yellow pine forest zone. The accumulation of several feet of snow during the winter is not uncommon and can stay on the ground for several months. The diversity of tree species found in this zone make this a beautiful and interesting forest to explore. The indicator species for the lower montane forest are the ponderosa pine and the Jeffrey pine: the ponderosa pine generally occurs on the west side of the Sierra, while the Jeffrey pine occurs on the east. The lower montane forests also include trees such as California black oak, sugar pine, incense-cedar, and white fir. Animals that may be found in this zone include the dark-eyed junco, mountain chickadee, western gray squirrel, mule deer, and American black bear. The endangered Yosemite toad is found in montane forests of the central Sierra Nevada, at elevations of .
 Links: a. Montane ecosystems b. Pinus jeffreyi c. Quercus kelloggii d. Quercus kelloggii
Example Output:
b