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: if 40 % of a certain number is 160 , then what is 90 % of that number ? 
Options: a ) 270 , b ) 380 , c ) 260 , d ) 360 , e ) 290
Example Output: d

Example Input: Problem: a ladder 14 feet long is leaning against a wall that is perpendicular to level ground . the bottom of the ladder is 5 feet from the base of the wall . if the top of the ladder slips down 4 feet , how many feet will the bottom of the ladder slip ? 
Options: a ) 4 , b ) 5 , c ) 8 , d ) 10.72 , e ) 15
Example Output: d

Example Input: Problem: a , b and c start a business each investing 2,000 . after 6 months a withdrew 1000 , b withdrew 1000 and c invests 1000 more . at the end of the year , a total profit of 6600 was recorded . find the share of b . 
Options: a ) 20,000 , b ) 21,200 , c ) 1,800 , d ) 20,500 , e ) none of these
Example Output:
c