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: john can complete a given task in 18 days. jane will take only 12 days to complete the same task. john and jane set out to complete the task by beginning to work together. however, jane was indisposed 6 days before the work got over. in how many days did the work get over from the time john and jane started to work on it together ?
Options: a. 11, b. 34 / 5, c. 44 / 5, d. 54 / 5, e. 12
Example Output: d

Example Input: Problem: what is the probability of getting a queen or spade from a set of cards ?
Options: a. 3 / 13, b. 4 / 13, c. 5 / 13, d. 6 / 13, e. 7 / 13
Example Output: b

Example Input: Problem: in a certain apartment building, there are one - bedroom and two - bedroom apartments. the rental prices of the apartment depend on a number of factors, but on average, two - bedroom apartments have higher rental prices than do one - bedroom apartments. let r be the average rental price for all apartments in the building. if r is $ 5,600 higher than the average rental price for all one - bedroom apartments, and if the average rental price for all two - bedroom apartments is $ 10,400 higher that r, then what percentage of apartments in the building are two - bedroom apartments ?
Options: a. 26 %, b. 35 %, c. 39 %, d. 42 %, e. 52 %
Example Output:
b