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: ages of two persons differ by 20 years . if 6 year ago , the elder one be 3 times as old the younger one , find their present age 
Options: a ) 12,28 , b ) 14,30 , c ) 16,36 , d ) 18,34 , e ) 19,34

Ex Output:
c


Ex Input:
Problem: how many even number in the range between 8 to 100 inclusive are not divisible by 3 
Options: a ) 15 , b ) 30 , c ) 32 , d ) 33 , e ) 46

Ex Output:
c


Ex Input:
Problem: if the sum of the first n positive integers is s , what is the sum of the first n negative even integers , in terms of s ? 
Options: a ) s / 2 , b ) s , c ) 2 s , d ) 2 s + 2 , e ) 4 s

Ex Output:

c