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 was the percentage share of the vote of Park's predecessor? Passage:Presidential elections were held in South Korea on 19 December 2012. They were the sixth presidential elections since democratization and the establishment of the Sixth Republic, and was held under a first-past-the-post system, in which there was a single round of voting and the candidate receiving the highest number of votes was elected. Under the South Korean constitution, presidents are restricted to a single five-year term in office. The term of incumbent president Lee Myung-bak ended on 24 February 2013. According to the Korea Times, 30.7 million people voted with turnout at 75.8%. Park Geun-hye of the Saenuri party was elected the first female South Korean president with 51.6% of the vote opposed to 48.0% for her opponent Moon Jae-in. Park's share of the vote was the highest won by any candidate since the beginning of free and fair direct elections in 1987.
Links: a. Lee Myung-bak b. Park Geun-hye c. History of South Korea d. Lee Myung-bak
Output:
a