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: what is the perimeter of a square field whose diagonal is 8 â ˆ š 2 ?
Options: a. 64 m, b. 32 m, c. 30 m, d. 16 m, e. 18 m
Example Output: b

Example Input: Problem: what is the median of a set of consecutive integers if the sum of nth number from the beginning and nth number from the end is 110 ?
Options: a. 10, b. 25, c. 55, d. 75, e. 100
Example Output: c

Example Input: Problem: at what rate percent on simple interest will rs. 1750 amount to rs. 2000 in 3 years ?
Options: a. 4 %, b. 3 6 / 7 %, c. 4.76 %, d. 5 %, e. 6 %
Example Output:
c