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: the average runs scored by a batsman in 20 matches is 40. in the next 10 matches the batsman scored an average of 30 runs. find his average in all the 30 matches ?
Options: a. 31, b. 36.67, c. 88, d. 13, e. 12
Example Output: b

Example Input: Problem: in n is a positive integer less than 200, and 14 n / 60 is an integer, then n has how many different positive prime factors s ?
Options: a. 2, b. 3, c. 5, d. 6, e. 8
Example Output: b

Example Input: Problem: of the 100 employees at company x, 80 are full - time, and 100 have worked at company x for at least a year. there are 20 employees at company x who aren ’ t full - time and haven ’ t worked at company x for at least a year. how many full - time employees of company x have worked at the company for at least a year ?
Options: a. 20, b. 30, c. 50, d. 80, e. 100
Example Output:
a