Given the task definition and input, reply with output. 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: In what order were the O'Mara sons born to Stephen O'Mara(listed by name)? Passage:O'Mara was the third son of Stephen O'Mara, Snr, a former Mayor of Limerick and briefly an Irish Parliamentary Party MP. Stephen Jr. married Nancy O'Brien and had a son, Peter. His elder brother James was an early supporter of Sinn Fein, which Stephen also joined after the Easter Rising. He was a member of Limerick Corporation when the Irish War of Independence began. The Mayor of Limerick, George Clancy, was killed by the Black and Tans on 7 March 1921, and O'Mara was elected in his place on 22 March. In May, he went to the United States to replace his brother James as "fiscal agent" raising Dail funds for the Irish Republic. He was re-elected mayor in January 1922, and opposed the Anglo-Irish Treaty. The fact that Dail Eireann funds in the US were in O'Mara's name as trustee caused legal difficulties for the pro-Treaty administration.
Links: a. Dail loans b. Stephen O'Mara (senator) c. Dail Eireann d. Sinn Fein
b