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: a is twice as good a work man as b and together they finish the work in 4 days. in how many days a alone can finish the work ?
Options: a. 3, b. 2, c. 7, d. 9, e. 6
Example Output: e

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: the simple interest on a sum of money will be rs. 1400 after 10 years. if the principal is trebled after 5 years what will be the total interest at the end of the tenth year ?
Options: a. 2800, b. 3799, c. 1200, d. 2693, e. 1732
Example Output:
a