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: a man deposits $ 2000 in a bank at 4 % per annum and $ 3000 in uti at 14 % per annum . find the rate of interest for the whole sum . 
Options: a ) 15 % , b ) 18 % , c ) 11 % , d ) 17 % , e ) 10 %
Example Output: d

Example Input: Problem: a dress on sale in a shop is marked at $ d . during the discount sale its price is reduced by 65 % . staff are allowed a further 60 % reduction on the discounted price . if a staff member buys the dress what will she have to pay in terms of d ? 
Options: a ) 0.15 d , b ) 0.16 d , c ) 0.65 d , d ) 0.14 d , e ) 0.05 d
Example Output: d

Example Input: Problem: running at the same constant rate , 6 identical machines can produce a total of 270 bottles per minute . at this rate , how many bottles could 10 such machines produce in 4 minutes ? 
Options: a ) 648 , b ) 1800 , c ) 2700 , d ) 10800 , e ) none
Example Output:
b