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.

Ex Input:
Problem: a batsman makes a score of 87 runs in the 17 th inning and thus increases his average by 3. find his average after 17 th inning.
Options: a. 39, b. 88, c. 26, d. 87, e. 11

Ex Output:
a


Ex Input:
Problem: if 9 / ( 1 + 4 / x ) = 1, then x =
Options: a. 3, b. 1 / 2, c. 1 / 3, d. - 1 / 3, e. - 3

Ex Output:
b


Ex Input:
Problem: two years ago, ram put $ 500 into a savings account. at the end of the first year, his account had accrued $ 100 in interest bringing his total balance to $ 600. the next year, his account balance increased by 10 %. at the end of the two years, by what percent has ram ' s account balance increased from his initial deposit of $ 500 ?
Options: a. 19 %, b. 28 %, c. 30 %, d. 32 %, e. 25 %

Ex Output:

d