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 grocer has a sale of rs. 5420, rs. 5660, rs. 6200, rs. 6350 and rs. 6500 for 5 consecutive months. find the sale he should have in the sixth month, so that he gets an average sale of rs. 6400 ?
Options: a. rs. 5870, b. rs. 8270, c. rs. 6020, d. rs. 6850, e. none of these

Ex Output:
b


Ex Input:
Problem: if the simple interest on a certain sum of money for 6 years is one – fifth of the sum, then the rate of interest per annum is
Options: a. 3.3 %, b. 7.2 %, c. 6.1 %, d. 5.0 %, e. 3.1 %

Ex Output:
a


Ex Input:
Problem: if jack walked 8 miles in 1 hour and 15 minutes, what was his rate of walking in miles per hour ?
Options: a. 4, b. 4.5, c. 6, d. 6.4, e. 15

Ex Output:

d