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 effective annual rate of interest corresponding to a nominal rate of 6 % per annum payable half - yearly is : 
Options: a ) 6.09 % , b ) 6.08 % , c ) 6.1 % , d ) 6.07 % , e ) 6.05 %
Example Output: a

Example Input: Problem: a reduction of 20 % in the price of oil enables a house wife to obtain 10 kgs more for rs . 1500 , what is the reduced price for kg ? 
Options: a ) rs . 20 , b ) rs . 25 , c ) rs . 30 , d ) rs . 35 , e ) rs . 40
Example Output: c

Example Input: Problem: running at the same rate , 8 identical machines can produce 560 paperclips a minute . at this rate , how many paperclips could 30 machines produce in 6 minutes ? 
Options: a ) 1344 , b ) 3360 , c ) 8400 , d ) 12600 , e ) 67200
Example Output:
d