Task: Question Answering
Input (English): Problem: if 2 ^ x + 2 ^ y = 10 ^ 0 + 90 ^ 0 , where x and y are non negative integers , what is the greatest possible value of | x â € “ y | ? 
Options: a ) 0 , b ) 1 , c ) 2 , d ) 3 , e ) 4
Output (English): a