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 retailer bought a machine at a wholesale price of $ 108 and later on sold it after a 10 % discount of the retail price . if the retailer made a profit equivalent to 20 % of the whole price , what is the retail price of the machine ? 
Options: a ) 81 , b ) 100 , c ) 120 , d ) 135 , e ) 144
Example Output: e

Example Input: Problem: a started a business with an investment of rs . 70000 and after 6 months b joined him investing rs . 120000 . if the profit at the end of a year is rs . 13000 , then the share of b is ? 
Options: a ) 6000 , b ) 12000 , c ) 18000 , d ) 24009 , e ) 24002
Example Output: a

Example Input: Problem: an investment yields an interest payment of $ 216 each month . if the simple annual interest rate is 9 % , what is the amount of the investment ? 
Options: a ) $ 28,300 , b ) $ 30,400 , c ) $ 28,800 , d ) $ 32,500 , e ) $ 35,100
Example Output:
c