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: in a division , a student took 72 as divisor instead of 36 . his answer was 24 . the correct answer is - 
Options: a ) 42 , b ) 32 , c ) 48 , d ) 28 , e ) 38

Ex Output:
c


Ex Input:
Problem: at the end of the month , a certain ocean desalination plant ’ s reservoir contained 14 million gallons of water . this amount is twice the normal level . if this amount represents 70 % of the reservoir ’ s total capacity , how many million gallons short of total capacity is the normal level ? 
Options: a ) 2 , b ) 5 , c ) 10 , d ) 12 , e ) 15

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 positive integers divisible by 4 , in terms of s ? 
Options: a ) s / 2 , b ) s , c ) 2 s , d ) 2 s + 2 , e ) 4 s

Ex Output:

e