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: anand finishes a work in 7 days, bittu finishes the same job in 8 days and chandu in 6 days. they take turns to finish the work. anand on the first day, bittu on the second and chandu on the third day and then anand again and so on. on which day will the work get over ?
Options: a. 3 rd, b. 6 th, c. 9 th, d. 7 th, e. 8 th
Example Output: d

Example Input: Problem: kathleen can paint a room in 4 hours, and anthony can paint an identical room in 5 hours. how many hours would it take kathleen and anthony to paint both rooms if they work together at their respective rates ?
Options: a. 8 / 15, b. 40 / 9, c. 15 / 8, d. 9 / 4, e. 15 / 4
Example Output: b

Example Input: Problem: in a village of 2,700 people, 900 people are over 70 years old and 1200 people are female. it is known that 60 percent of the females are younger than 70 years old. if no one in the village is 70 years old, what is the probability that a person chosen at random is either a male or younger than 70 years old ?
Options: a. 4 / 5, b. 5 / 7, c. 13 / 15, d. 37 / 45, e. 79 / 90
Example Output:
d