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 wages of 6 men for 15 days be rs. 2100, then find the wages of for 12 days.
Options: a. rs. 2420, b. rs. 2500, c. rs. 2520, d. rs. 2020, e. rs. 2650

Ex Output:
c


Ex Input:
Problem: the speed of the boat in still water in 12 kmph. it can travel downstream through 54 kms in 3 hrs. in what time would it cover the same distance upstream ?
Options: a. 8 hours, b. 6 hours, c. 4 hours, d. 5 hours, e. 9 hours

Ex Output:
e


Ex Input:
Problem: two pipes a and b can fill a tank in 36 hours and 46 hours respectively. if both the pipes are opened simultaneously, how much time will be taken to fill the tank ?
Options: a. 20.195 hrs, b. 21.195 hrs, c. 22.195 hrs, d. 23.195 hrs, e. 20.495 hrs

Ex Output:

a