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: if the price of a certain computer increased 30 percent from b dollars to 351 dollars, then 2 b =
Options: a. 540, b. 570, c. 619, d. 649, e. 700
Example Output: a

Example Input: Problem: sheila works 8 hours per day on monday, wednesday and friday, and 6 hours per day on tuesday and thursday. she does not work on saturday and sunday. she earns $ 360 per week. how much does she earn in dollars per hour ?
Options: a. 11, b. 10, c. 9, d. 8, e. 7
Example Output: b

Example Input: Problem: the operation is defined for all integers a and b by the equation ab = ( a - 1 ) ( b - 1 ). if y 12 = 110, what is the value of y ?
Options: a. 11, b. 12, c. 13, d. 15, e. 18
Example Output:
a