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 escalator moves towards the top level at the rate of 12 ft . sec and its length is 160 feet . if a person walks on the moving escalator at the rate of 8 feet per second towards the top level , how much time does he take to cover the entire length . 
Options: a ) 10 sec , b ) 8 sec , c ) 9 sec , d ) 7 sec , e ) 12 sec
Example Output: b

Example Input: Problem: a man ' s speed with the current is 12 km / hr and the speed of the current is 2 km / hr . the man ' s speed against the current is 
Options: a ) 8 , b ) 10 , c ) 11 , d ) 12 , e ) 13
Example Output: a

Example Input: Problem: a towel , when bleached , lost 20 % of its length and 20 % of its breadth . what is the percentage decrease in area ? 
Options: a ) 24 % , b ) 36 % , c ) 32 % , d ) 54 % , e ) 64 %
Example Output:
b