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: a train 510 m long is running at a speed of 45 km / hr. in what time will it pass a bridge 140 m long ?
Options: a. 40, b. 52, c. 26, d. 21, e. 14

Output: b


Input: Consider Input: Problem: a jar full of whisky contains 40 % alcohol. a part of this whisky is replaced by another containg 17 % alcohol and now the percentage of alcohol was found to be 26 %. what quantity of whisky is replaced ?
Options: a. 1 / 3, b. 2 / 3, c. 2 / 5, d. 3 / 5, e. 4 / 5


Output: c