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 student travels from his house to school at 12 km / hr and reaches school 2 hours late. the next day he travels 20 km / hr and reaches school 1 hour early. what is the distance between his house and the school ?
Options: a. 90, b. 100, c. 110, d. 120, e. 130

Ex Output:
a


Ex Input:
Problem: a can finish a work in 60 days, b in 9 days and c in 2 days, b and c start the work but are forced to leave after 3 days. the remaining work was done by a in ?
Options: a. 10 days, b. 25 days, c. 6 days, d. 7 days, e. 8 days

Ex Output:
b


Ex Input:
Problem: vijay lent out an amount rs. 10000 into two parts, one at 8 % p. a. and the remaining at 10 % p. a. both on simple interest. at the end of the year he received rs. 890 as total interest. what was the amount he lent out at 8 % pa. a ?
Options: a. 5529, b. 5500, c. 5520, d. 5521, e. 5192

Ex Output:

b