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: if p / q = 2 / 7 , then 2 p + q = ? 
Options: a ) 11 , b ) 14 , c ) 13 , d ) 15 , e ) 16
Example Output: a

Example Input: Problem: if the sales tax reduced from 3 1 / 2 % to 3 1 / 3 % , then what difference does it make to a person who purchases an article with market price of rs . 10800 ? 
Options: a ) 11 , b ) 13 , c ) 14 , d ) 18 , e ) 10
Example Output: d

Example Input: Problem: if x + y = 20 , x - y = 36 , for integers of x and y , x = ? 
Options: a ) 20 , b ) 25 , c ) 28 , d ) 20 , e ) 42
Example Output:
c