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: you and your friend spent a total of $ 19 for lunch . your friend spent $ 3 more than you . how much did your friend spend on their lunch ?
Options: a ) $ 9 , b ) $ 3 , c ) $ 4 , d ) $ 6 , e ) $ 11
Example Output: e

Example Input: Problem: the average age of 7 men increases by 4 years when two women are included in place of two men of ages 26 and 30 years . find the average age of the women ?
Options: a ) 42 , b ) 40 , c ) 30 , d ) 18 , e ) 11
Example Output: a

Example Input: Problem: if the operation is defined for all positive integers x and w by x w = ( 2 ^ x ) / ( 2 ^ w ) then ( 3 1 ) 1 = ?
Options: a ) 2 , b ) 4 , c ) 8 , d ) 16 , e ) 32
Example Output:
c