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: 8597 - ? = 7429 - 4358 
Options: a ) 3567 , b ) 6424 , c ) 6835 , d ) 5526 , e ) none of these
Example Output: d

Example Input: Problem: find the average of first 4 multiples of 15 ? 
Options: a ) 10 , b ) 12.6 , c ) 22.5 , d ) 31.3 , e ) 37.5
Example Output: e

Example Input: Problem: the sum of the first 50 positive even integers is 2,550 . what is the sum of the odd integers from 101 to 200 , inclusive ? 
Options: a ) 5,050 , b ) 7,500 , c ) 10,500 , d ) 15,000 , e ) 19,600
Example Output:
b