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: the perimeter of an isosceles right triangle is 12 + 12 sq rt 2. what is the length of the hypotenuse of the triangle ?
Options: ['a. 5', 'b. 6', 'c. 7', 'd. 8.485', 'e. 8']

Ex Output:
d

Ex Input:
Problem: on the independence day, bananas were be equally distributed among the children in a school so that each child would get two bananas. on the particular day 360 children were absent and as a result each child got two extra bananas. find the actual number of children in the school ?
Options: a. 237, b. 287, c. 197, d. 287, e. 720

Ex Output:
e

Ex Input:
Problem: a dog takes 5 leaps for every 7 leaps of a hare. if one leap of the dog is equal to 3 leaps of the hare, the ratio of the speed of the dog to that of the hare is :
Options: a. 16: 7, b. 15: 7, c. 20: 7, d. 7: 15, e. 14: 7

Ex Output:
b