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: a cricket player whose bowling average was 21.5 runs per wicket, takes 5 wicket for 52 runs in a match. due to this his average decreases by 0.5. what will be the number of wickets taken by him till the last match ?
Options: a. 64, b. 72, c. 111, d. 721, e. 108
Example Output: c

Example Input: Problem: a store reported total sales of $ 460 million for february of this year. if the total sales for the same month last year was $ 320 million, approximately what was the percent increase in sales ?
Options: a. 2 %, b. 17 %, c. 44 %, d. 65 %, e. 83 %
Example Output: c

Example Input: Problem: the food in a camp lasts for 10 men for 20 days. if 30 more men join, how many days will the food last ?
Options: a. 8 days, b. 4 days, c. 5 days, d. 10 days, e. 17 days
Example Output:
c