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: of all the homes on gotham street, 1 / 3 are termite - ridden, and 4 / 7 of these are collapsing. what fraction of the homes are termite - ridden, but not collapsing ?
Options: a. 1 / 3, b. 1 / 4, c. 1 / 5, d. 1 / 6, e. 1 / 7

Output: e


Input: Consider Input: Problem: if a train, travelling at a speed of 90 kmph, crosses a pole in 4 sec, then the length of train is ?
Options: a. 281, b. 125, c. 288, d. 100, e. 121

Output: d


Input: Consider Input: Problem: martin bought 10 concert tickets, some at the full price of $ 2.00 per ticket, and some at a discounted price of $ 1.60 per ticket. if he spent a total of $ 18.80, how many discounted tickets did he buy ?
Options: a. 3, b. 4, c. 5, d. 6, e. 7


Output: a