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: the sum of 4 consecutive even numbers is 140. what would be the smallest number ?
Options: a. 32, b. 88, c. 70, d. 123, e. 12

Ex Output:
a


Ex Input:
Problem: a thief is spotted by a policeman from a distance of 150 meters. when the policeman starts the chase, the thief also starts running. if the speed of the thief be 8 km / hr and that of the policeman 10 km / hr, how far the thief will have run before he is overtaken ?
Options: a. 350 m, b. 200 m, c. 400 m, d. 600 m, e. none of them

Ex Output:
d


Ex Input:
Problem: a alone can do a piece of work in 6 days and b alone in 8 days. a and b undertook to do it for rs. 6000. with the help of c, they completed the work in 3 days. how much is to be paid to c ?
Options: a. s. 375, b. s. 400, c. s. 600, d. s. 750, e. s. 850

Ex Output:

d