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: excluding the stoppages, the speed of a bus is 48 km / hr and including the stoppages the speed of the bus is 12 km / hr. for how many minutes does the bus stop per hour ?
Options: a. 45 min, b. 10 min, c. 12 min, d. 20 min, e. 18 min

Ex Output:
a


Ex Input:
Problem: when a certain number x is divided by 61, the remainder is 24. what is the remainder when x is divided by 5 ?
Options: a. 2, b. 3, c. 4, d. 5, e. 6

Ex Output:
c


Ex Input:
Problem: carol spends 1 / 4 of her savings on a stereo and 1 / 2 less than she spent on the stereo for a television. what fraction of her savings did she spend on the stereo and television ?
Options: a. 1 / 4, b. 2 / 7, c. 5 / 12, d. 3 / 8, e. 7 / 12

Ex Output:

d