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: an error 10 % in excess is made while measuring the side of a square . now what is the percentage of error in the calculated area of the square ? 
Options: a ) 6.64 % , b ) 16.64 % , c ) 15.64 % , d ) 21 % , e ) 10.64 %
Example Output: d

Example Input: Problem: you hold some gold in a vault as an investment . over the past year the price of gold increases by 60 % . in order to keep your gold in the vault , you must pay 10 % of the total value of the gold per year . what percentage has the value of your holdings changed by over the past year . 
Options: a ) 45 % , b ) 46 % , c ) 50 % , d ) 55 % , e ) 44 %
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 . 78000 , then the share of a is ? 
Options: a ) s . 42028 , b ) s . 42000 , c ) s . 42003 , d ) s . 42029 , e ) s . 24029
Example Output:
b