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: an investor deposited $ 10,000 to open a new savings account that earned 12 percent annual interest, compounded quarterly. if there were no other transactions in the account, what was the amount of money in the account 6 months after the account was opened ?
Options: a. $ 10,300, b. $ 10,303, c. $ 10,600, d. $ 10,609, e. $ 10,900

Ex Output:
d

Ex Input:
Problem: if ( 1 1.25 ) n = 4, then n =
Options: a. 400, b. 16, c. 4, d. 4, e. 400

Ex Output:
b

Ex Input:
Problem: how many diagonals does a 60 - sided convex polygon have ?
Options: a. 960, b. 1280, c. 1710, d. 2560, e. 3420

Ex Output:
c