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: sandy walked 20 meters towards south. then sandy turned to her left and walked 20 meters. she then turned to her left and walked 20 meters. she then turned to her right and walked 25 meters. what distance is she from the starting point and in which direction ?
Options: a. 35 m east, b. 35 m north, c. 30 m west, d. 45 m west, e. 45 m east
Example Output: e

Example Input: Problem: a sum of money at simple interest amounts to $ 645 in 3 years and to $ 690 in 4 years. the sum is :
Options: a. $ 153, b. $ 510, c. $ 598, d. $ 549, e. $ 675
Example Output: b

Example Input: Problem: a committee is reviewing a total of 40 x black - and - white films and 10 y color films for a festival. if the committee selects y / x % of the black - and - white films and all of the color films, what fraction of the selected films are in color ?
Options: a. 50 / 52, b. 55 / 52, c. 60 / 52, d. 40 / 52, e. 30 / 52
Example Output:
a