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'.

Ex Input:
Problem: a seller of used cars has 16 cars to sell and each of his clients selected 2 cars that he liked most . if each car was selected exactly thrice , how many clients visited the garage ? 
Options: a ) 8 , b ) 10 , c ) 12 , d ) 14 , e ) 24

Ex Output:
e


Ex Input:
Problem: if a : b = 2 : 3 , b : c = 4 : 5 and c : d = 5 : 9 then a : d is equal to : 
Options: a ) 11 : 17 , b ) 8 : 27 , c ) 5 : 9 , d ) 2 : 9 , e ) none

Ex Output:
b


Ex Input:
Problem: the average age of a , b and c is 26 years . if the average age of a and c is 29 years , what is the age of b in years ? 
Options: a ) 19 , b ) 35 , c ) 20 , d ) 32 , e ) 21

Ex Output:

c