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: a dishonest dealer claims to sell a product at its cost price . he uses a counterfeit weight which is 20 % less than the real weight . further greed overtook him and he added 15 % impurities to the product . find the net profit percentage of the dealer ?
Options: a ) 46.85 % , b ) 43.75 % , c ) 50 % , d ) 56.25 % , e ) 36 %
Example Output: b

Example Input: Problem: the ration of the father ' s age to his son ' s age is 7 : 3 . the product of their ages is 756 . the ratio of their ages after 6 years will be :
Options: a ) 5 : 2 , b ) 2 : 1 , c ) 11 : 7 , d ) 13 : 9 , e ) none of these
Example Output: b

Example Input: Problem: the maximum number of students among them 1340 pens and 1280 pencils can be distributed in such a way that each student get the same number of pens and same number of pencils ?
Options: a ) 25 , b ) 30 , c ) 20 , d ) 45 , e ) 90
Example Output:
c