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.

Input: Consider Input: Problem: the average of 11 10 prime numbers which are odd is ?
Options: a. 17.72, b. 18.52, c. 19.63, d. 16.53, e. 15.63

Output: a

Input: Consider Input: Problem: students at a school were on average 180 cm tall. the average female height was 170 cm, and the average male height was 182 cms. what was the ratio of men to women ?
Options: a. 5: 2, b. 5: 1, c. 4: 3, d. 4: 1, e. 3: 1

Output: b

Input: Consider Input: Problem: a retailer bought a machine at a wholesale price of $ 90 and later on sold it after a 10 % discount of the retail price. if the retailer made a profit equivalent to 20 % of the whole price, what is the retail price r of the machine ?
Options: a. 81, b. 100, c. 120, d. 135, e. 160
Output: c