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: in a class of students , 2 / 3 of the number of girls is equal to 1 / 4 of the total number of students . what is the ratio of boys to girls in the class ? 
Options: a ) 1 / 3 , b ) 2 / 3 , c ) 4 / 3 , d ) 5 / 3 , e ) 7 / 3
Example Output: d

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: 40 liters of a mixture is created by mixing liquid p and liquid q in the ratio 5 : 3 . how many liters of liquid q must be added to make the ratio 5 : 6 ? 
Options: a ) 5 , b ) 8 , c ) 10 , d ) 12 , e ) 15
Example Output:
e