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: peter invested a certain sum of money in a simple interest bond whose value grew to $ 100 at the end of 2 years and further to $ 200 at the end of another 4 years . what was the rate of interest in which he invested his sum ? 
Options: a ) 50 % , b ) 25 % , c ) 10 % , d ) 30 % , e ) 18 %
Example Output: a

Example Input: Problem: a shopkeeper sells his goods at cost price but uses a faulty meter that weighs 800 grams . find the profit percent . 
Options: a ) 20 , b ) 15 , c ) 25 , d ) 18 , e ) 19
Example Output: c

Example Input: Problem: from the sale of sleeping bags , a retailer made a gross profit of 16 % of the wholesale cost . if each sleeping bag was sold for $ 28 , what was the wholesale cost per bag ? 
Options: a ) 3.0 , b ) 3.36 , c ) 24.13 , d ) 25.0 , e ) 31.36
Example Output:
c