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: four bells commence tolling together and toll at intervals of 2, 4, 6, 8 seconds respectively. in 18 minutes, how many times do they toll together ?
Options: a. 43, b. 44, c. 45, d. 46, e. 47

Output: c


Input: Consider Input: Problem: the ` ` racing magic ' ' takes 120 seconds to circle the racing track once. the ` ` charging bull ' ' makes 40 rounds of the track in an hour. if they left the starting point together, how many minutes will it take for them to meet at the starting point for the second time ?
Options: a. 3, b. 6, c. 9, d. 12, e. 15

Output: d


Input: Consider Input: Problem: a can do a piece of work in 10 days and b can do it in 15 days and c can do it 20 days. they started the work together and a leaves after 5 days and b leaves after 3 days from the beginning. how long will work lost ?
Options: a. 2, b. 4, c. 5, d. 6, e. 7


Output: d