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: a bag contains 10 green and 8 white balls. if two balls are drawn simultaneously, the probability that both are of the same colour is
Options: a. 8 / 15, b. 21 / 44, c. 3 / 5, d. 11 / 15, e. 7 / 15

Ex Output:
b


Ex Input:
Problem: a man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. the ratio of the speed of the boat in still water and stream is
Options: a. 3: 1, b. 1: 3, c. 2: 4, d. 4: 2, e. none of these

Ex Output:
a


Ex Input:
Problem: what is the sum between the place values of two 3 ' s in the numeral 63130
Options: a. 3111, b. 300, c. 3029, d. 3030, e. 3003

Ex Output:

d