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.

Ex Input:
Problem: a movie buff buys movies on dvd and on blu - ray in a ratio of 13: 4. if she returns 2 blu - ray movies, that ratio would change to 7: 2. if she buys movies on no other medium, what was the original number of movies purchased ?
Options: a. 22, b. 28, c. 77, d. 99, e. 119

Ex Output:
e


Ex Input:
Problem: a merchant sells an item at a 20 % discount, but still makes a gross profit of 20 percent of the cost. what percent of the cost would the gross profit on the item have been if it had been sold without the discount ?
Options: a. 20 %, b. 40 %, c. 50 %, d. 60 %, e. 75 %

Ex Output:
c


Ex Input:
Problem: a is twice as good a workman as b and together they complete a work in 12 days. in how many days a alone can do the work ?
Options: a. 32, b. 33, c. 34, d. 35, e. 36

Ex Output:

e