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.

Ex Input:
Problem: micheal and adam can do together a piece of work in 20 days. after they have worked together for 15 days micheal stops and adam completes the remaining work in 10 days. in how many days micheal complete the work separately.
Options: a. 40 days, b. 100 days, c. 120 days, d. 110 days, e. 90 days

Ex Output:
a


Ex 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

Ex Output:
c


Ex Input:
Problem: the average age of 15 students of a class is 15 years. out of these, the average age of 5 students is 14 years and that of the other 9 students is 16 years, the age of the 15 th student is
Options: a. 11, b. 15, c. 6, d. 8, e. 76

Ex Output:

a