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: how many prime numbers are between 29 / 3 and 87 / 6 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5

Output: b


Input: Consider Input: Problem: the length of the bridge, which a train 130 metres long and travelling at 45 km / hr can cross in 30 seconds, is
Options: a. 200 m, b. 225 m, c. 245 m, d. 250 m, e. none


Output: c