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: 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

Ex Output:
d


Ex Input:
Problem: 10 is added to a certain number , the sum is multiplied by 2 , the product is divided by 2 and 2 is subtracted from the quotient . the remainder left is half of 88 . what is the number ? 
Options: a ) 21 , b ) 20 , c ) 25 , d ) 36 , e ) 45

Ex Output:
d


Ex Input:
Problem: what is the average ( arithmetic mean ) of all multiples of 10 from 10 to 100 inclusive ? 
Options: a ) 190 , b ) 195 , c ) 200 , d ) 205 , e ) 55

Ex Output:

e