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: the largest 5 digit number exactly divisible by 91 is : 
Options: a ) 25698 , b ) 581396 , c ) 369741 , d ) 99918 , e ) 1258
Example Output: d

Example Input: Problem: what is the average of first 21 multiples of 5 ? 
Options: a ) a ) 70 , b ) b ) 77 , c ) c ) 55 , d ) d ) 81 , e ) e ) 82
Example Output: c

Example Input: Problem: if 75 percent of 600 is 50 percent of x , then x = ? 
Options: a ) 800 , b ) 900 , c ) 1000 , d ) 1100 , e ) 1200
Example Output:
b