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: What is the difference in age between Campbell and his brother-in-law? Passage:He was born at Bedford Square, London, January 4, 1809. He grew up in an affluent family, the fifth of the six children born to Duncan Campbell (d.1815), who had made a fortune in the West Indies, and Harriet (d.1817), daughter of Robert Young of Auchenshcoch. He was the grandson of Alexander Campbell (1710-1760), 11th Laird of Inverawe, Argyll, descended from Archibald Campbell of Inverawe. His brother, Colonel James Campbell, built New Inverawe, today known as Ardanaiseig Hotel. He was a brother-in-law of Sir Alexander Spearman 1st Bt., of Hanwell, and his sister-in-law was a niece of Lt.-General Sir James Campbell, 1st Bt., of Inverneill. In 1832, he graduated from the Royal Military Academy Sandhurst and was appointed Captain of the Royal Scots and aide-de-camp to Lieutenant-General Campbell. He transferred to the 1st The Royal Dragoons and then joined the 7th Queen's Own Hussars, serving in the Near East.
Links: a. Clan Campbell b. Aide-de-camp c. Spearman baronets d. Bedford Square
Output:
c