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: a shopkeeper sold 30 articles at the cost price of 35 articles. then find the profit % or lost %
Options: a. 12 %, b. 15 %, c. 16.67 %, d. 18 %, e. 22 %

Ex Output:
c


Ex Input:
Problem: at a certain university, 65 % of the professors are women, and 70 % of the professors are tenured. if 90 % of the professors are women, tenured, or both, then what percent of the men are tenured ?
Options: a. 25, b. 37.5, c. 50, d. 62.5, e. 75

Ex Output:
d


Ex Input:
Problem: find the compound interest on $ 1200 for 6 years at 20 % p. a. if ci is component yearly ?
Options: a. $ 120, b. $ 150, c. $ 2383, d. $ 250, e. $ 300

Ex Output:

c