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 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 Bridger–Teton 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: When did the event where  Frank Alberry won a Distinguished Conduct Medal end? Passage:Frank Alberry, DCM (29 September 1892 – 23 January 1968) was an Australian soldier and airman who had a varied military career. Born in Hobart, he served in the Welch Regiment of the British Army before the First World War, but deserted. He joined up again in the early days of the First World War, and went on to serve with the 8th Battalion of the Australian Imperial Force. After service at Gallipoli, he joined the British Expeditionary Force in France. He won a Distinguished Conduct Medal at the Battle of Pozières, but lost a lower leg in the process. Alberry took the extraordinary step of personally petitioning King George V for permission to transfer to the Flying Corps, and subsequently became a flying ace credited with seven aerial victories. Alberry returned to service during the Second World War as a recruiter.
 Links: a. Distinguished Conduct Medal b. Battle of Pozières c. 8th Battalion (Australia) d. World War II
Example Output: b

Example Input: Question: What age was Pirow when his fascist group was formed? Passage:Nazism found an audience in the country, with pro-Nazi elements organised by Louis Weichardt in 1932 under the name South African Gentile National Socialist Movement, a group that soon became known as the Greyshirts. Although the group enjoyed some support and continued after the Second World War they never became sufficiently important for the government to take action against them. The other main fascist group was the Ossewabrandwag (OB), founded in 1939, a group also inspired by Adolf Hitler. The two differed however as the Greyshirts emphasised Aryan race rhetoric and so organised amongst the various white immigrant communities whilst the OB were specifically for Afrikaner only. A third, more minor group, the New Order, emerged in 1940 under the leadership of former cabinet minister Oswald Pirow. After the Second World War Pirow became an important figure in neo-fascism, working closely with Oswald Mosley, Nation Europa and A. F. X. Baron. Nazi Germany sought to encourage such activity with former Olympic boxer Robey Leibbrandt active as an agent for the Abwehr during the war. The Nazi Party itself also organised until it was outlawed in 1936.
 Links: a. Oswald Pirow b. Nation Europa c. Nation Europa d. Nazism
Example Output:
a