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: sum of two numbers is 63 . their difference is 1 / 8 of their sum . their l . c . m is 
Options: a ) 231 , b ) 153 , c ) 351 , d ) 345 , e ) 355
Example Output: c

Example Input: Problem: a is two years older than b who is twice as old as c . if the total of the ages of a , b and c be 12 , the how old is b ? 
Options: a ) 10 years , b ) 4 years , c ) 6 years , d ) 15 years , e ) 16 years
Example Output: b

Example Input: Problem: there are 3 prizes to be distributed among 10 students . if no students gets more than one prize , then this can be done in ? 
Options: a ) 10 , b ) 45 , c ) 95 , d ) 120 , e ) none of these
Example Output:
d