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: 108 a 108 + 92 a 92 = ?
Options: a. 20120, b. 11500, c. 20128, d. 20660, e. 20228

Output: c

Input: Consider 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

Output: d

Input: Consider Input: Problem: a train running at the speed of 100 km / hr crosses a pole in 9 sec. what is the length of the train ?
Options: a. 298 m, b. 250 m, c. 208 m, d. 988 m, e. 299 m
Output: b