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: ( 18 ) 7 x ( 5832 ) - 2 ÷ ( 324 ) - 1 = ( 18 ) 7 
Options: a ) 5 , b ) 4 , c ) 3 , d ) 2 , e ) 1

Ex Output:
c


Ex Input:
Problem: the difference of two numbers is 11 and one - fifth of their sum is 9 . find the numbers . 
Options: a ) 28 and 17 , b ) 27 and 18 , c ) 25 and 15 , d ) 27 and 15 , e ) 25 and 18

Ex Output:
a


Ex Input:
Problem: how many multiples of 5 are there between 10 and 100 , exclusive ? 
Options: a ) 18 , b ) 17 , c ) 16 , d ) 15 , e ) 14

Ex Output:

b