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: a man swims downstream 36 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water ?
Options: a. 7, b. 8, c. 9, d. 2, e. 4

Output: c


Input: Consider Input: Problem: what is the perimeter of a square field whose diagonal is 8 â ˆ š 2 ?
Options: a. 64 m, b. 32 m, c. 30 m, d. 16 m, e. 18 m

Output: b


Input: Consider Input: Problem: lloyd normally works 7.5 hours per day and earns $ 3.50 per hour. for each hour he works in excess of 7.5 hours on a given day, he is paid 1.5 times his regular rate. if lloyd works 10.5 hours on a given day, how much does he earn for that day ?
Options: a. $ 33.75, b. $ 42.00, c. $ 51.75, d. $ 54.00, e. $ 70.00


Output: b