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.

Input: Consider Input: Problem: a person purchases 90 clocks and sells 40 clocks at a gain of 10 % and 50 clocks at a gain of 20 %. if he sold all of them at a uniform profit of 15 %, then he would have got rs. 40 less. the cost price of each clock is :
Options: a. 50, b. 90, c. 80, d. 28, e. 93

Output: c


Input: Consider Input: Problem: if s is the sum of reciprocals of a list of consecutive integers from 55 to 64, inclusive, s is approximately equal to
Options: a. 0.16, b. 0.2, c. 0.3, d. 0.4, e. 0.5

Output: a


Input: Consider Input: Problem: a box contain the number of balls which is as much greater than 44 is less than 70. the number of balls is ?
Options: a. 47, b. 114, c. 74, d. 67, e. 57


Output: e