You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Example Input: Question: Two pipes A and B can fill a cistern in 20 and 30 minutes respectively, and a third pipe C can empty it in 40 minutes. How long will it take to fill the cistern if all the three are opened at the same time?

 Option A: 17 1/5

 Option B: 17 1/8

 Option C: 17 1/7

 Option D: 17 1/1

 Option E: 17 1/2
Example Output: Option C

Example Input: Question: If x and y are integers, what is the least positive number of 24x+18y?

 Option A: 3

 Option B: 6

 Option C: 9

 Option D: 12

 Option E: 15
Example Output: Option B

Example Input: Question: If x is to be chosen at random from the set {1, 2, 3, 4} and y is to be chosen at random from the set {5, 6, 7}, what is the probability that xy will be odd?

 Option A:  1/6

 Option B:  1/3

 Option C:  1/2

 Option D:  2/3

 Option E:  5/6
Example Output:
Option B