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.

Ex Input:
Question: Look at this series: 15, 15, 27, 27, 39, 39, 51, 51, 63, 63, ? ... What number should fill the blank?

 Option A: 51

 Option B: 39

 Option C: 75

 Option D: 15

 Option E: None

Ex Output:
Option C


Ex Input:
Question: The average runs scored by a batsman in 20 matches is 40. In the next 10 matches the batsman scored an average of 20 runs. Find his average in all the 30 matches?

 Option A: 31

 Option B: 46

 Option C: 88

 Option D: 33.33

 Option E: 12

Ex Output:
Option D


Ex Input:
Question: A and B together can do a piece of work in 6 days and A alone can do it in 9 days. In how many days can B alone can do it?

 Option A: 12 days

 Option B: 15 days

 Option C: 18 days

 Option D: 21 days

 Option E: 22 days

Ex Output:

Option C