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: what sum of money will produce rs. 80 as simple interest in 4 years at 3 1 / 2 percent ?
Options: a. 263, b. 571.4, c. 367, d. 368, e. 339

Ex Output:
b

Ex Input:
Problem: 108 a 108 + 92 a 92 = ?
Options: a. 20120, b. 11500, c. 20128, d. 20660, e. 20228

Ex Output:
c

Ex Input:
Problem: if y is the smallest positive integer such that 7350 multiplied by y is the square of an integer, then y must be
Options: a. 2, b. 5, c. 6, d. 7, e. 14

Ex Output:
c