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.

Example 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
Example Output: b

Example Input: Problem: if a lends rs. 3150 to b at 8 % per annum and b lends the same sum to c at 12.5 % per annum then the gain of b in a period of 2 years is ?
Options: a. 280, b. 295, c. 283.5, d. 245, e. 200
Example Output: c

Example Input: Problem: workers at a campaign office have 2000 fliers to send out. if they send out 1 / 4 of them in the morning and 1 / 5 of the remaining ones out during the afternoon, how many are left for the next day ?
Options: a. 300, b. 800, c. 1100, d. 1200, e. 1180
Example Output:
e