Definition: 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'.
Input: Problem: a person ' s present age is one - fifth of the age of his mother . after 8 years , he will be one - half of the age of his mother . how old is the mother at present ?
Options: a ) a ) 25 , b ) b ) 44 , c ) c ) 32 , d ) d ) 45 , e ) e ) 40
Output:
e