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: barbata invests $ 2200 in the national bank at 5 %. how much additional money must she invest at 8 % so that the total annual income will be equal to 6 % of her entire investment ?
Options: a. 1100, b. 3000, c. 1000, d. 3600, e. 2400

Ex Output:
a


Ex Input:
Problem: the cash realised on selling a 14 % stock is rs. 109.25, brokerage being 1 / 4 % is ?
Options: a. 366, b. 106, c. 102, d. 109, e. 122

Ex Output:
d


Ex Input:
Problem: there is a square with side ‘ a ’ and one octagon is inscribed in it. what will be perimeter of octagon.
Options: ['a. 8 a / 3', 'b. 7 a / 3', 'c. 5 a / 3', 'd. a / 3', 'e. 11 a / 3']

Ex Output:

a