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: One water pump can fill half of a certain empty tank in 7 hours. Another pump can fill half of the same tank in 7.5 hours. Working together, how long will it take these two pumps to fill the entire tank?

 Option A: 7 7/13

 Option B: 1 5/8

 Option C: 3 1/4

 Option D: 7 7/29

 Option E: 3 1/2
Example Output: Option D

Example Input: Question: A certain sum earns simple interest of Rs. 800 in 2 years at a certain rate of interest. If the same sum earns compound interest of Rs.900in the same period of 2 years, What must be the rate of interest?

 Option A: 25%

 Option B: 10%

 Option C: 15%

 Option D: 20%

 Option E: 30%
Example Output: Option A

Example Input: Question: A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?

 Option A: 277 m

 Option B: 268 m

 Option C: 276 m

 Option D: 150 m

 Option E: 125 m
Example Output:
Option D