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 compound interest paid on a sum of rs. 3000 for the period of 2 years at 10 % per annum.
Options: a. 630, b. 620, c. 610, d. 600, e. none of these

Ex Output:
a


Ex Input:
Problem: during a given week a programmer spends 1 / 4 of his time preparing flow chart, 3 / 8 of his time coding and the rest of the time in debugging the programs. if he works 48 hours during the week, how many hours did he spend debugging the program.
Options: a. 15 hrs, b. 16 hrs, c. 18 hrs, d. 19 hrs, e. 17 hrs

Ex Output:
c


Ex Input:
Problem: in the xy - coordinate system, if ( m, n ) and ( m + 2, n + k ) are two points on the line perpendicular to x = 2 y + 5, then k = ?
Options: a. - 5, b. - 8, c. 2, d. - 4, e. 1

Ex Output:

d