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 had Shumilov been in the military when the Soviet invaded Poland? Passage:Colonel (promoted to Major General 4 June 1940) Mikhail Shumilov took command in April 1938. In September 1939, the corps fought in the Soviet invasion of Poland as part of the 10th Army. It included the 6th, 33rd, and the 121st Rifle Divisions at the beginning of the invasion on 17 September. By 2 October, these divisions had transferred to other units, and it included the 29th, 64th, and 145th Rifle Divisions instead. The corps headquarters relocated to Grodno in November and became part of the 11th Army. Between June and July 1940 it was briefly headquartered at Kovno before moving to Siauliai in August, part of the Baltic Special Military District. The 11th transferred to the 8th Army in October, and included the 11th and 125th Rifle Divisions by the outbreak of the war. It defended a 40-kilometer sector on the left flank of the 8th Army, with its headquarters in the forests northwest of Skaudvile. The 125th Rifle Division was in the corps' first echelon, holding covering the highway and railroad from Tilsit to Siauliai. The 48th Rifle Division (part of the adjacent 10th Rifle Corps), after moving forward from Riga, was to take up positions on the left of the 125th. The corps' 73rd Corps Artillery Regiment included four battalions of 107 mm guns.
Links: a. Mikhail Shumilov b. 11th Rifle Division c. 10th Rifle Corps d. Baltic Military District
Example Output: a

Example Input: Question: Which modernist sculptor is younger, Joseph Csaky or Jean Arp? Passage:In 1953, the foundation's collecting criteria expanded under its new director, James Johnson Sweeney. Sweeney rejected Rebay's dismissal of "objective" painting and sculpture, and he soon acquired Constantin Brancusi's Adam and Eve (1921), followed by works of other modernist sculptors, including Joseph Csaky, Jean Arp, Calder, Alberto Giacometti and David Smith. Sweeney reached beyond the 20th century to acquire Paul Cezanne's Man with Crossed Arms (c. 1899). The same year, the foundation also received a gift of 28 important works from the Estate of Katherine S. Dreier, a founder of America's first collection to be called a modern art museum, the Societe Anonyme. Dreier had been a colleague of Rebay's. The works included Little French Girl (191418) by Brancusi, an untitled still life (1916) by Juan Gris, a bronze sculpture (1919) by Alexander Archipenko and three collages (191921) by German Hanoverian Dadaist Schwitters. It also included works by Calder, Marcel Duchamp, El Lissitzky and Mondrian. Among others, Sweeney also acquired the works of Alberto Giacometti, David Hayes, Willem de Kooning and Jackson Pollock.
Links: a. Joseph Csaky b. Jackson Pollock c. Constantin Brancusi d. Marcel Duchamp
Example Output: a

Example Input: Question: In what city was Watson a laboratory staff member from 1957 to 1981? Passage:Watson graduated in 1943 with BS in electrical engineering from Iowa State College. From 1943 to 1946 he was a researcher at the United States Naval Research Laboratory in Washington, D.C. During his work for the U.S. Navy he went to night school at George Washington University. He graduated from the University of Iowa with Ph.D. in 1948 with thesis The polarizability of the meson-charge cloud of a neutron in an external electrostatic field. He was from 1948 to 1949 an Atomic Energy Commission (AEC) Fellow at the Institute for Advanced Study and from 1949 to 1951 an AEC Fellow at the Berkeley Radiation Laboratory. He was from 1951 to 1954 an assistant professor of physics at Indiana University and from 1954 to 1957 an associate professor of physics at the University of Wisconsin, Madison. In 1953 he was elected a fellow of the American Physical Society. From 1957 to 1981 he was a staff member of Lawrence Berkeley National Laboratory, as well as a professor of physics at the University of California, Berkeley. In 1974 he was elected a member of the National Academy of Sciences. From 1981 to 1991 he was the director of the Marine Physical Laboratory, Scripps Institute of Oceanography, as well as a professor of physical oceanography at the University of California, San Diego. In 1991 he retired as professor emeritus. His doctoral students include Shang-keng Ma.
Links: a. George Washington University b. University of Iowa c. Lawrence Berkeley National Laboratory d. American Physical Society
Example Output:
c