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: reena took a loan of $ . 1200 with simple interest for as many years as the rate of interest . if she paid $ 588 as interest at the end of the loan period , what was the rate of interest ? 
Options: a ) 3.6 , b ) 7 , c ) 18 , d ) can not be determined , e ) none of these
Example Output: b

Example Input: Problem: what is 15 percent of 44 ? 
Options: a ) 6.6 , b ) 7.8 , c ) 8.9 , d ) 9.4 , e ) 10.2
Example Output: a

Example Input: Problem: a towel , when bleached , lost 20 % of its length and 10 % of its breadth . what is the percentage decrease in area ? 
Options: a ) 26 , b ) 28 , c ) 24 , d ) 20 , e ) 22
Example Output:
b