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 often are new issues of the Canadian Journal of Neurological Sciences published? Passage:Multi-dose versions of the vaccine contain the preservative thiomersal (also known as thimerosal), a mercury compound that prevents contamination when the vial is used repeatedly. Single-dose versions and the live vaccine do not contain this preservative. In the U.S., one dose from a multi-dose vial contains approximately 25 micrograms of mercury, a bit less than a typical tuna fish sandwich. In Canada, different variants contain five and 50 micrograms of thimerosal per dose. The use of thiomersal has been controversial, with claims that it can cause autism and other developmental disorders. The U.S. Institute of Medicine examined these claims and concluded in 2004 that the evidence did not support any link between vaccines and autism. Other reviews came to similar conclusions, with a 2006 review in the Canadian Journal of Neurological Sciences stating that there is no convincing evidence to support the claim that thimerosal has a causal role in autism, and a 2009 review in the journal Clinical Infectious Diseases stating that claims that mercury can cause autism are "biologically implausible". The U.K. National Health Service stated in 2003 that "There is no evidence of long-term adverse effects due to the exposure levels of thiomersal in vaccines." The World Health Organization concluded that there is "no evidence of toxicity in infants, children or adults exposed to thiomersal in vaccines". Indeed, in 2008 a review noted that even though thiomersal was removed from all US childhood vaccines in 2001, this has not changed the number of autism diagnoses, which are still increasing.
 Links: a. Thiomersal and vaccines b. Autism c. Canadian Journal of Neurological Sciences d. National Academy of Medicine
Example Output: c

Example Input: Question: Is the person who served as Lebanese President during 1982 still alive? Passage:According to historians William Cleveland and Martin Bunton, Beirut became an international banking center because of its “laissez-faire economic system”. Business owners from Cairo, Damascus, and Baghdad moved to Beirut for economic opportunities. Despite Lebanon’s cultural liberalism and economic prosperity, sectarian tensions remained as citizens identified themselves through their sects. With Muslims calling for greater representation and with Cold War tensions, Lebanese leadership had to decide whether to ally with the West or with Egypt, Syria and its Arab history. Christians wanted to continue alliances with the West but Muslims were drawn to Nasser's pan-Arabism. Multiple factors including sectarian tensions and Palestinian refugee settlement in southern Lebanon contributed to the beginnings of the Lebanese Civil War. In 1976, Syrian President Hafez al-Assad sent troops into Lebanon to fight PLO forces on behalf of Christian militias. This led to escalated fighting until a cease-fire agreement later that year that allowed for the stationing of Syrian troops within Lebanon. The Syrian presence in Lebanon quickly changed sides; soon after they entered Lebanon they had flip-flopped and began to fight the Christian nationalists in Lebanon they allegedly entered the country to protect. The Kateab Party and the Lebanese Forces under Bachir Gemayel strongly resisted the Syrians in Lebanon. Following the Israeli invasion into Lebanon in 1982, new Lebanese President Amine Gemayel sought the support of Syrian troops to stabilize the region. Syria fought Israeli troops after the latter's invasion of Lebanon.
 Links: a. Israel Defense Forces b. Egypt c. Amine Gemayel d. Cairo
Example Output: c

Example Input: Question: Which of the districts in which he was a liberal member held more seats in 1967? Passage:He was born at Launceston in Tasmania to draper Alexander Morrison McLaren and Elsie Elizabeth Gibbins. He attended Caulfield Grammar School and then the University of Melbourne, becoming an accountant. In 1938 he embarked on a world tour, returning in 1939. He served in the Royal Australian Navy from 1942 to 1945 and returned to become a partner in the accountancy firm Harris & McLaren. On 16 April 1941 he married Eileen Porter, with whom he had four children. From 1945 to 1947 he was the independent member for Glen Iris in the Victorian Legislative Assembly. Following his defeat he joined the Liberal Party, and served on Malvern City Council from 1951 to 1953. From 1957 to 1963 he was national president of the YMCA, and he served as world vice-president from 1961 to 1969; he was also awarded the OBE in 1959. In 1965 he returned to the Legislative Assembly as the Liberal member for Caulfield, changing seats to Bennettswood in 1967. From 1973 he was Deputy Speaker. McLaren retired from politics in 1979, and died in 2000.
 Links: a. City of Malvern b. Electoral district of Caulfield c. YMCA d. Independent politician
Example Output:
b