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: if the average ( arithmetic mean ) of a and b is 45 and the average of b and c is 80, what is the value of c − a ?
Options: a. 25, b. 60, c. 90, d. 140, e. it can not be determined from the information given.

Output: b


Input: Consider Input: Problem: find value for x from below equation ? x + 1 = - 3
Options: a. 1, b. - 4, c. - 1, d. 2, e. 3

Output: b


Input: Consider Input: Problem: the average age of a, b and c is 26 years. if the average age of a and c is 29 years, what is the age of b in years ?
Options: a. 19, b. 35, c. 20, d. 32, e. 21


Output: c