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: how many positive integers less than 1000 are multiples of 5 but not of 4 or 7 ? 
Options: a ) 114 , b ) 121 , c ) 122 , d ) 129 , e ) 136

Ex Output:
c


Ex Input:
Problem: caleb spends $ 64.50 on 50 hamburgers for the marching band . if single burgers cost $ 1.00 each and double burgers cost $ 1.50 each , how many double burgers did he buy ? 
Options: a ) 29 , b ) 10 , c ) 20 , d ) 40 , e ) 45

Ex Output:
a


Ex Input:
Problem: john was thrice as old as tom 6 years ago . john will be 15 / 13 times as old as tom in 6 years . how old is tom today ? 
Options: a ) 5 , b ) 7 , c ) 9 , d ) 11 , e ) 13

Ex Output:

b