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: A cycle is bought for Rs.900 and sold for Rs.1150, find the gain percent?

 Option A: 15

 Option B: 20

 Option C: 27.77

 Option D: 40

 Option E: 12
Example Output: Option C

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: What is the greatest prime factor of 4^16 - 2^30?

 Option A: 2

 Option B: 3

 Option C: 5

 Option D: 7

 Option E: 11
Example Output:
Option B