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: mahesh marks an article 15 % above the cost price of rs . 540 . what must be his discount percentage if he sells it at rs . 460 ? 
Options: a ) 18 % , b ) 21 % , c ) 25.9 % , d ) 19 % , e ) none of these
Example Output: c

Example Input: Problem: a sum was put at simple interest at a certain rate for 3 years . had it been put at 2 % higher rate , it would have fetched rs . 360 more . find the sum . 
Options: a ) 3000 , b ) 6000 , c ) 2000 , d ) 4000 , e ) none of them
Example Output: b

Example Input: Problem: running at the same rate , 8 identical machines can produce 560 paperclips a minute . at this rate , how many paperclips could 12 machines produce in 6 minutes ? 
Options: a ) 1344 , b ) 3360 , c ) 8400 , d ) 5040 , e ) 67200
Example Output:
d