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: 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

Ex Output:
a


Ex Input:
Problem: if 5400 mn = k ^ 4 , where m , n , and k are positive integers , what is the least possible value of m + 2 n ? 
Options: a ) 11 , b ) 18 , c ) 20 , d ) 25 , e ) 40

Ex Output:
e


Ex Input:
Problem: in 1950 , richard was 4 times as old as robert . in 1955 , richard was 3 times as old as robert . in which year was richard 1.25 as old as robert ? 
Options: a ) 1960 , b ) 1965 , c ) 1970 , d ) 2050 , e ) 2060

Ex Output:

e