In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: the ration of the father ' s age to his son ' s age is 7 : 3 . the product of their ages is 756 . the ratio of their ages after 6 years will be :
Options: a ) 5 : 2 , b ) 2 : 1 , c ) 11 : 7 , d ) 13 : 9 , e ) none of these
Example Output: b

Example Input: Problem: the difference between a 7 digit number and the number formed by reversing its digit is not a multiple of
Options: a ) 121 , b ) 11 , c ) 9 , d ) 10 , e ) 3
Example Output: a

Example Input: Problem: let exp ( m , n ) = m to the power n . if exp ( 10 , m ) = n exp ( 22 ) where m and n are integers then n = ___ ?
Options: a ) 24 , b ) 25 , c ) 26 , d ) 27 , e ) 28
Example Output:
b