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.

Example Input: Problem: if ( 1 – 1.25 ) n = 4, then n =
Options: a. − 400, b. − 16, c. − 4, d. 4, e. 400
Example Output: b

Example Input: Problem: in a mayoral election, candidate x received 1 / 2 more votes than candidate y, and candidate y received 2 / 5 fewer votes than z. if z received 25000 votes how many votes did candidate x received ?
Options: a. 18000, b. 22500, c. 24000, d. 26000, e. 32000
Example Output: b

Example Input: Problem: the marks obtained by vijay and amith are in the ratio 6: 5 and those obtained by amith and abhishek in the ratio of 3: 2. the marks obtained by vijay and abhishek are in the ratio of ?
Options: a. 1: 5, b. 4: 5, c. 9: 5, d. 9: 8, e. 9: 7
Example Output:
c