Definition: 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.
Input: Question: If x and y are integers such that x^2= y and xy = 27, then x – y = ?

 Option A: -30

 Option B: -20

 Option C: -6

 Option D: 5

 Option E: 20

Option C