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 value of 10 ^ 7 - 6 ^ 5 ? 
Options: a ) 99 , 91,223 , b ) 99 , 92,224 , c ) 99 , 94,265 , d ) 99 , 95,300 , e ) 99 , 96,307
Example Output: b

Example Input: Problem: a , b and c have rs . 450 between them , a and c together have rs . 200 and b and c rs . 350 . how much does c have ? 
Options: a ) a ) 100 , b ) b ) 110 , c ) c ) 120 , d ) d ) 130 , e ) e ) 140
Example Output: a

Example Input: Problem: a man is 18 years older than his son . in eight years , his age will be twice the age of his son . the present age of this son is 
Options: a ) 5 years , b ) 10 years , c ) 15 years , d ) 20 years , e ) 25 years
Example Output:
b

