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 the military president of Pakistan when he decided to build a new capital? Passage:Islamabad officially became the capital of Pakistan on 14 August 1967, exactly 20 years after the country's independence. The first capital of Pakistan was the coastal city of Karachi in Sindh, which was selected by Muhammad Ali Jinnah. Karachi was and still is the largest city and economic capital of Pakistan. It remained the seat of government until 1959, when the military president, Ayub Khan, decided to build a new capital, Islamabad in the north of Pakistan, near the general headquarters of the Pakistani Armed Forces which is in Rawalpindi. During this process, Rawalpindi was the interim capital. The name of Islamabad was influenced from the Mughal name of the Bengali port city of Chittagong which was Islamabad.
Links: a. Ayub Khan (general) b. Pakistan Armed Forces c. Karachi d. Rawalpindi
Output:
a