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: how many integers v are prime numbers in the range 200 < v < 220 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5
Example Output: a

Example Input: Problem: how many multiples of 4 are there between 12 and 104, inclusive ?
Options: a. 21, b. 22, c. 23, d. 24, e. 25
Example Output: d

Example Input: Problem: a sells a bicycle to b and makes a profit of 25 %. b sells the same bicycle to c at a profit of 50 %. if the final s. p. of the bicycle was rs. 225, find out the cost price of the bicycle for a.
Options: a. 237, b. 126, c. 971, d. 611, e. 120
Example Output:
e