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: what is the rate percent when the simple interest on rs. 720 amount to rs. 180 in 4 years ?
Options: a. 6.25, b. 7.25, c. 8.25, d. 9.25, e. 10.25

Ex Output:
a


Ex Input:
Problem: if the perimeter of a rectangular garden is 700 m, its length when its breadth is 100 m is ?
Options: a. 299 m, b. 777 m, c. 200 m, d. 250 m, e. 128 m

Ex Output:
d


Ex Input:
Problem: a sum of rs. 2730 is lent into two parts so that the interest on the first part for 8 years at 3 % per annum may be equal to the interest on the second part for 3 years at 5 % per annum. find the second sum ?
Options: a. 1629, b. 1680, c. 1677, d. 1698, e. 1679

Ex Output:

b