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: if n is a natural number , then ( 6 n ^ 2 + 6 n ) is always divisible by 
Options: a ) 6 only , b ) 6 and 12 both , c ) 12 only , d ) 18 only , e ) 12 and 18 both
Example Output: b

Example Input: Problem: what is the smallest no . which must be added to 532869 so as to obtain a sum which is divisible by 9 ? 
Options: a ) 9 , b ) 2 , c ) 1 , d ) 3 , e ) 6
Example Output: d

Example Input: Problem: find the principle on a certain sum of money at 5 % per annum for 2 2 / 5 years if the amount being rs . 1792 ? 
Options: a ) 1600 , b ) 2777 , c ) 2889 , d ) 27670 , e ) 2771
Example Output:
a