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: in an office, totally there are 2800 employees and 25 % of the total employees are males. 30 % of the males in the office are at - least 50 years old. find the number of males aged below 50 years ?
Options: a. 390, b. 490, c. 400, d. 460, e. none of these

Ex Output:
b


Ex Input:
Problem: a particular library has 75 books in a special collection, all of which were in the library at the beginning of the month. these book are occasionally loaned out through an inter - library program. if, by the end of the month, 80 percent of books that were loaned out are returned and there are 67 books in the special collection at that time, how many books of the special collection were loaned out during that month ?
Options: a. 20, b. 30, c. 35, d. 40, e. 55

Ex Output:
d


Ex Input:
Problem: there are 2 sections a and b in a class, consisting of 50 and 50 students respectively. if the average weight of section a is 60 kg and that of section b is 80 kg, find the average of the whole class ?
Options: a. 50.78 kg, b. 49.32 kg, c. 61.67 kg, d. 70 kg, e. 70.89 kg

Ex Output:

d