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: how many 3 - digit numbers are divisible by 6 in all ? 
Options: a ) 149 , b ) 150 , c ) 151 , d ) 166 , e ) none
Example Output: b

Example Input: Problem: what is the next number 12 13 15 17 111 113 117 119 123 129 ? 
Options: a ) 154 , b ) 220 , c ) 129 , d ) 131 , e ) 224
Example Output: d

Example Input: Problem: in x game of billiards , x can give y 20 points in 60 and he can give z 30 points in 60 . how many points can y give z in x game of 100 ? 
Options: a ) 30 , b ) 20 , c ) 25 , d ) 40 , e ) 50
Example Output:
c