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 was Montana's population the year that Thom Ross completed his work "Custer's Last Stand"? Passage:Ross' first plywood installation was a 1976 cutout of Clint Eastwood, which he and a friend placed as a prank above a railroad trestle to recreate a scene from Dirty Harry in the location where the scene had been filmed five years earlier. In 1983 Ross created "154 Nevermore", an installation of 154 plywood ravens on a highway in Jackson, Wyoming (recreated in steel in 2000). In 1984, Ross created "the Catch", a diorama for the Baseball Hall of Fame illustrating a legendary catch with the same nickname, by Willie Mays in the 1954 World Series. He created a new version of the work in 2004, and displayed it in various locations in New York City. In 1998 Ross created "The Defining Moment" for SAFECO Field, a tableau of 11 steel cutouts of a Ken Griffey, Junior play in the 1995 baseball playoffs. Ross' 2005 work, "Custer's Last Stand", was a recreation of life-sized warriors riding life-sized horses the Battle of Little Bighorn at the original site at Medicine Tail Coulee in Montana. That exhibit toured Cody, Wyoming, Jackson, Wyoming, and Sun Valley, Idaho. In September, 2008 Ross recreated a 1902 photograph of Buffalo Bill Cody and his "Wild West Show", his traveling troupe of Native Americans, in front of the Cliff House at Ocean Beach.
 Links: a. National Baseball Hall of Fame and Museum b. Battle of the Little Bighorn c. Montana d. T-Mobile Park
Example Output: c

Example Input: Question: How many years was Taft president? Passage:Howard was born to Ossian Gregory Howard, a lawyer, and Lucy Denham Thurber on 11 June 1857. His relatives from his mother's side included the Harvard astronomer E.C. Pickering while other distant relatives included Senator J.M. Howard and President William Howard Taft. Shortly after his birth, the family moved from Rockford, to Ithaca, New York where his father worked with a law firm. Howard attended Ithaca Academy. An interest in insect collecting encouraged by his parents with the gift of The Butterfly Hunters by Mary Treat at the age of 10 followed by more books and at the age of 13, along with another collector friend, recorded the introduction of the European cabbage butterfly (Pieris rapae) in the Catskill region. Along with his friends, he founded the Ithaca Natural History Society to meet and discuss papers and insects. While out collecting one day, he met John Henry Comstock, who invited him to his lab at Cornell University. Howard enrolled in Cornell in September 1873, three years after the death of his father, and following the advice of his mother's friends, went to study civil engineering. Doing poorly in differential calculus made him drop engineering and he began to study other subjects including French, German, and Italian. He then joined Comstock's lab as the first research student and graduated in June 1877 with a thesis on respiration in the larva of Corydalis cornutus. He worked with Burt Green Wilder and Simon Henry Gage and received a masters at Cornell. In the 1880s, he also attended Columbian College (now George Washington University) for medicine, although he didn't complete it. He however received an honorary MD from the same university in 1911 for his contribution to medical entomology. 
 Links: a. William Howard Taft b. Rockford, Illinois c. John Henry Comstock d. Pieris rapae
Example Output: a

Example Input: Question: How many species of pigeons are there? Passage:The spotted green pigeon or Liverpool pigeon (Caloenas maculata) is a species of pigeon which is most likely extinct. It was first mentioned and described in 1783 by John Latham, who had seen two specimens of unknown provenance and a drawing depicting the bird. The taxonomic relationships of the bird were long obscure, and early writers suggested many different possibilities, though the idea that it was related to the Nicobar pigeon (C. nicobarica) prevailed, and it was therefore placed in the same genus, Caloenas. Today, the species is only known from a specimen kept in World Museum, Liverpool. Overlooked for much of the 20th century, it was recognised as a valid extinct species by the IUCN Red List only in 2008. In 2014 a genetic study confirmed it as a distinct species related to the Nicobar pigeon, and showed that the two were the closest relatives of the extinct dodo and Rodrigues solitaire.
 Links: a. Provenance b. Species description c. Columbidae d. Dodo
Example Output:
c