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.

Example Input: Problem: a man can row upstream at 25 kmph and downstream at 55 kmph, and then find the speed of the man in still water ?
Options: a. 65, b. 40, c. 30, d. 78, e. 38
Example Output: b

Example 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
Example Output: b

Example Input: Problem: 9. on level farmland, two runners leave at the same time from the intersection of two country roads. one runner jogs due north at a constant rate of 8 miles per hour while the second runner jogs due east at a constant rate that is 8 miles per hour faster than the first runner ' s rate. how far apart, to the nearest mile, will they be after 1 / 2 hour ?
Options: a. 6, b. 7, c. 8, d. 12, e. 9
Example Output:
e