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: If f(y)=y^2 and y is a positive integer, which of the following CANNOT be the value of f(f(y))?

 Option A: 1

 Option B: 144

 Option C: 81

 Option D: 16

 Option E: 256
Example Output: Option B

Example Input: Question: What is the area of an equilateral triangle whose one side length is 80?

 Option A: 800√3

 Option B: 1000√3

 Option C: 1200√3

 Option D: 1400√3

 Option E: 1600√3
Example Output: Option E

Example Input: Question: Rohit spent 50 percent of his earning last month on rent and 30 percent less than what he spent on rent to purchase a new dishwasher. What percent of last month's earning did John have left over?

 Option A: 15%

 Option B: 25%

 Option C: 35%

 Option D: 55%

 Option E: 20%
Example Output:
Option A