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 x : y = 3 : 5 , find the value of ( 2 x + 4 y ) : ( 3 x – y ) 
Options: a ) 13 : 2 , b ) 11 : 2 , c ) 13 : 3 , d ) 13 : 4 , e ) 13 : 5
Example Output: a

Example Input: Problem: a certain lab experiments with white and brown mice only . in one experiment , 2 / 3 of the mice are white . if there are 11 brown mice in the experiment , how many mice in total are in the experiment ? 
Options: a ) 39 , b ) 33 , c ) 26 , d ) 21 , e ) 10
Example Output: b

Example Input: Problem: if xy = 9 , x / y = 36 , for positive numbers x and y , y = ? 
Options: a ) 1 / 2 , b ) 2 , c ) 1 / 3 , d ) 3 , e ) 1 / 6
Example Output:
a