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: if the simple interest on a certain amount in at 4 % rate 5 years amounted to rs. 2240 less than the principal. what was the principal ?
Options: a. 1500, b. 2500, c. 2507, d. 2800, e. 11500

Ex Output:
d


Ex Input:
Problem: if ( 1 – 1.25 ) n = 4, then n =
Options: a. − 400, b. − 16, c. − 4, d. 4, e. 400

Ex Output:
b


Ex Input:
Problem: pipe a fills a tank in 12 minutes. pipe b can fill the same tank 3 times as fast as pipe a. if both the pipes are kept open when the tank is empty, how many minutes will it take to fill the tank ?
Options: a. 4 mins, b. 6 mins, c. 5 mins, d. 3 mins, e. 7 mins

Ex Output:

d