Instructions: 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: Problem: on a saturday night, each of the rooms at a certain motel was rented for either $ 40 or $ 60. if 10 of the rooms that were rented for $ 60 had instead been rented for $ 40, then the total rent the motel charged for that night would have been reduced by 40 percent. what was the total rent the motel actually charged for that night ?
Options: a. $ 500, b. $ 800, c. $ 1,000, d. $ 1,600, e. $ 2,400
Output:
a