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: ray writes a two digit number. he sees that the number exceeds 4 times the sum of its digits by 3. if the number is increased by 18, the result is the same as the number formed by reversing the digits. find the number.
Options: a. 2, b. 5, c. 6, d. 7, e. 8

Ex Output:
b

Ex Input:
Problem: if ( 2 ^ 16 ) ( 25 ^ s ) = 5 ( 10 ^ m ) what is the value of m ?
Options: a. 7, b. 8, c. 15, d. 16, e. 23

Ex Output:
d

Ex Input:
Problem: praveen starts business with rs. 3920 and after 5 months, hari joins with praveen as his partner. after a year, the profit is divided in the ratio 2: 3. what is hari ' s contribution in the capital ?
Options: a. s. 10080, b. s. 8000, c. s. 8500, d. s. 9000, e. s. 6000

Ex Output:
a