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 worker earns $ 20 on the first day and spends $ 15 on the second day. the worker earns $ 20 on the third day and spends $ 15 on the fourth day. if this pattern continues, on which day will the worker first reach a net total of $ 80 ?
Options: a. 24, b. 25, c. 27, d. 30, e. 32

Ex Output:
b


Ex Input:
Problem: for the past n days, the average ( arithmetic mean ) daily production at a company was 50 units. if today ' s production of 110 units raises the average to 55 units per day, what is the value of n ?
Options: a. 9, b. 11, c. 13, d. 15, e. 17

Ex Output:
b


Ex Input:
Problem: the monthly rent of a shop of dimension 18 feet × 22 feet is rs. 2244. what is the annual rent per square foot of the shop ? ( a. rs. 5 ( 2 / 3 )
Options: a. 43, b. 56, c. 68, d. 87, e. 92

Ex Output:

c