You will be given a definition of a task first, then some input of the task.
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.

Question: How old was John Pershing when he graduated from the United States Military Academy? Passage:The son of a Union Army veteran of the American Civil War, Penn was born in Mattoon, Illinois and raised in Batavia, Ohio. He graduated from the United States Military Academy in 1886, and was a classmate and close friend of John J. Pershing. After graduation, he served in the Western United States as a member of the 13th and 2nd Infantry Regiments, and he was an 1891 graduate of the Infantry and Cavalry School, the predecessor of the Command and General Staff College. During the SpanishAmerican War, Penn served as a quartermaster officer at Camp George H. Thomas, Georgia and the Tampa mobilization point before contracting typhoid. After recovering, he was assigned to the Philippines, where he commanded 2nd Battalion, 34th Infantry. Penn's post-war assignments included service with the 7th Infantry in the Philippines, aide to General Henry Clark Corbin, and commander of provisional battalions in the 7th and 12th Infantry Regiments. He was a 1907 graduate of the Army War College, and during the Pancho Villa Expedition, Penn commanded the 3rd Infantry Regiment in Texas.
Links: a. SpanishAmerican War b. 13th Infantry Regiment (United States) c. John J. Pershing d. Batavia, Ohio
Output:
c