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: find the curved surface area, if the radius of a cone is 35 m and slant height is 30 m ?
Options: a. 1100, b. 2200, c. 3300, d. 4400, e. 5500
Example Output: c

Example Input: Problem: find the value o f 72519 x 9999 = m ?
Options: a. 434539873, b. 355797990, c. 435453490, d. m = 725117481, e. 873430134
Example Output: d

Example Input: Problem: find the value of ( 100 + 20 / 90 ) 90
Options: a. 4520, b. 9100, c. 9150, d. 8120, e. 9020
Example Output:
e