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: bob wants to run a mile in the same time as his sister. if bob ’ s time for a mile is currently 11 minutes 20 seconds and his sister ’ s time is currently 9 minutes 36 seconds, by what percent does bob need to improve his time in order run a mile in the same time as his sister ?
Options: a. 3 %, b. 5 %, c. 8 %, d. 10 %, e. 15 %

Ex Output:
e


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: the distance between 2 cities a and b is 1000 km. a train starts from a at 10 a. m. and travels towards b at 100 km / hr. another starts from b at 11 a. m. and travels towards a at 150 km / hr. at what time do they meet ?
Options: a. 11 am., b. 12 p. m., c. 3 pm., d. 2 p. m., e. 1 p. m.

Ex Output:

c