In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: the cost price of 16 articles is the same as the selling price of 12 articles . find the loss / profit percentages . 
Options: a ) 30 % , b ) 32.50 % , c ) 33 1 / 3 % , d ) 40 % , e ) 50 %
Example Output: c

Example Input: Problem: a is a working partner and b is a sleeping partner in the business . a puts in rs . 3500 and b rs . 1500 , a receives 10 % of the profit for managing the business the rest being divided in proportion of their capitals . out of a total profit of rs . 9600 , money received by a is ? 
Options: a ) 1978 , b ) 2707 , c ) 7728 , d ) 7008 , e ) 7291
Example Output: d

Example Input: Problem: sam invested $ 1000 @ 20 % per annum for one year . if the interest is compounded half yearly , then the amount received by sam at the end of the year will be ? 
Options: a ) $ 1542 , b ) $ 1145 , c ) $ 1210 , d ) $ 1642 , e ) $ 1020
Example Output:
c