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'.

Example Input: Problem: what is the greatest integer m for which the number 30 ! / 10 ^ m is an integer ? 
Options: a ) 7 , b ) 8 , c ) 9 , d ) 10 , e ) 11
Example Output: a

Example Input: Problem: the sum of three consecutive even numbers multiples of 3 is 72 . what is the largest number ? 
Options: a ) 21 , b ) 24 , c ) 27 , d ) 36 , e ) none
Example Output: c

Example Input: Problem: what is the difference between the largest number and the least number written with the digits 9 , 2 , 1 , 5 ? 
Options: a ) 6084 , b ) 3788 , c ) 2077 , d ) 8262 , e ) 1812
Example Output:
d