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: jar a has 6 % more marbles than jar b . what percent of marbles from jar a need to be moved into jar b so that both jars have equal marbles ? 
Options: a ) 2.8 % , b ) 3.0 % , c ) 3.2 % , d ) 3.4 % , e ) 3.6 %
Example Output: a

Example Input: Problem: a towel , when bleached , lost 30 % of its length and 20 % of its breadth . what is the percentage decrease in area ? 
Options: a ) 24 % , b ) 30 % , c ) 44 % , d ) 54 % , e ) 64 %
Example Output:
c