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: two trains of equal are running on parallel lines in the same direction at 45 km / hr and 36 km / hr. the faster train passes the slower train in 36 sec. the length of each train is ?
Options: a. 45, b. 88, c. 66, d. 55, e. 22

Ex Output:
a


Ex Input:
Problem: if a no. when divided by 44, gives 432 as quotient and 0 as remainder. what will be the remainder when dividing thesame no. by 31
Options: a. 2, b. 4, c. 5, d. 7, e. 8

Ex Output:
c


Ex Input:
Problem: a tailor trims 6 feet from opposite edges of a square piece of cloth, and 5 feet from the other two edges. if 80 square feet of cloth remain, what was the length of a side of the original piece of cloth ?
Options: a. 16, b. 18, c. 20, d. 24, e. 32

Ex Output:

c