Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Example Input: Problem: the total age of a and b is 16 years more than the total age of b and c. c is how many year younger than
Options: a. 14 years, b. 12 years, c. 56 years, d. 16 years, e. 55 years
Example Output: d

Example Input: Problem: if an investor puts $ 700 in a savings account that earns 10 percent annual interest compounded semiannually, how much money will be in the account after one year ?
Options: a. $ 769.75, b. $ 771.75, c. $ 773.75, d. $ 775.75, e. $ 777.75
Example Output: b

Example Input: Problem: in a recent election, geoff received 15 percent of the 6,000 votes cast. to win the election, a candidate needed to receive more than x % of the vote. if geoff needed exactly 3,571 more votes to win the election, what is the value of x ?
Options: a. 74.5, b. 54, c. 56, d. 60, e. 63
Example Output:
a