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 old was Derow's teacher and lasting influence at Oxford when Derow graduated from Oxford? Passage:Born in Newport, Rhode Island, Derow obtained his secondary education at The Roxbury Latin School in West Roxbury, Massachusetts. After an A.B. degree at Amherst (with Peter K. Marshall), he read for Greats as a second B.A. degree at Oxford in 19651967, achieving a First. At Oxford he was taught by, among others, W. G. (George) Forrest, who was a lasting influence. He completed a Ph.D. at Princeton on 'Rome and the Greek world from the earliest contacts to the end of the first Illyrian war', for which Professor J. V. A. Fine was his Advisor; in the preface to that work, he acknowledges the additional inspiration he had drawn from T. J. Luce and the historian and epigrapher C. Bradford Welles. After a spell of teaching at the University of Toronto, he returned to succeed Forrest at Wadham in 1977 when the latter was elected to the Wykeham Professorship of Ancient History at New College. In 20022005 Derow was also Director of Graduate Studies in ancient history for the Oxford Faculty of Classics.
Links: a. George Forrest (historian) b. Roxbury Latin School c. Roxbury Latin School d. Princeton University
Example Output: a

Example Input: Question: How long is the river that's located in western Sweetwater County? Passage:It rises in western Wyoming, in northern Sublette County, on the western side of the Continental Divide in the BridgerTeton National Forest in the Wind River Range. It flows south through Sublette County and western Wyoming in an area known as the Upper Green River Valley, then southwest and is joined by the Big Sandy River in western Sweetwater County. At the town of La Barge, it flows into Fontenelle Reservoir, formed by Fontenelle Dam. Below there, it flows through open sage covered rolling prairie where it is crossed by the Oregon, California and Mormon emigration trails and then further south until it flows past the town of Green River and into the Flaming Gorge Reservoir in Southwestern Wyoming, formed by the Flaming Gorge Dam in northeastern Utah. Prior to the creation of the reservoir, the Blacks Fork joined the Green River south of Green River, today the mouth of Blacks Fork is submerged by the reservoir.
Links: a. Big Sandy River (Wyoming) b. Flaming Gorge Reservoir c. Sweetwater County, Wyoming d. Mormon Trail
Example Output: a

Example Input: Question: Who founded the institute that in 2007 stated that within five years real GDP would increase 10.7% over the current system? Passage:In an open letter to the President, the Congress, and the American people, eighty economists, including Nobel Laureate Vernon L. Smith, stated that the FairTax would boost the United States economy. According to the National Bureau of Economic Research and Americans For Fair Taxation, GDP would increase almost 10.5% in the year after the FairTax goes into effect. Real investments could increase by as much as 76% initially and remain 15% above present levels. In addition, the incentive to work would increase by as much as 20%, the economy's capital stock would increase by 42%, labor supply by 4%, output by 12%, and real wage rate by 8%. A study in 2007 by the Beacon Hill Institute of Suffolk University stated that within five years real GDP would increase 10.7% over the current system, domestic investment by 86.3%, capital stock by 9.3%, employment by 9.9%, real wages by 10.2%, and consumption by 1.8%. Laurence Kotlikoff of Boston University finds that the shift to the FairTax would raise marginal labor productivity and real wages over the course of the century by 18.9% and long-run output by 10.6%. Further, studies of the FairTax at Boston University and Rice University suggests the FairTax will bring long-term interest rates down by as much as one third. As falling tax compliance costs lower production costs, exports would increase by 26% initially and remain more than 13% above present levels. According to Professor Dale Jorgenson of Harvard University's Economics Department, revenues to Social Security and Medicare would double as the size of the economy doubles within 15 years after passage of the FairTax. Wall Street Journal columnist James Taranto states the FairTax is unsuited to take advantage of supply-side effects and would create a powerful disincentive to spend money.
Links: a. The Wall Street Journal b. James Taranto c. Beacon Hill Institute d. Rice University
Example Output:
c