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: a group of hikers is planning a trip that will take them up a mountain using one route and back down using another route. they plan to travel down the mountain at a rate of one and a half times the rate they will use on the way up, but the time each route will take is the same. if they will go up the mountain at a rate of 7 miles per day and it will take them two days, how many miles long is the route down the mountain ?
Options: a. 18, b. 19, c. 20, d. 21, e. 22

Ex Output:
d


Ex Input:
Problem: the shopkeeper sale, all of the prices of the items sold were different. if the price of a radio sold at the shopkeeper sale was both the 9 th highest price and the 14 th lowest price among the prices of the items sold, how many items were sold at the shopkeeper sale ?
Options: a. 23, b. 22, c. 32, d. 26, e. 17

Ex Output:
b


Ex Input:
Problem: the average of temperatures at noontime from monday to friday is 60; the lowest one is 40, what is the possible maximum range of the temperatures ?
Options: a. 100, b. 25, c. 40, d. 45, e. 75

Ex Output:

a