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: a bowl was filled with 10 ounces of water , and 0.014 ounce of the water evaporated each day during a 50 - day period . what percent of the original amount of water evaporated during this period ? 
Options: a ) 0.004 % , b ) 0.04 % , c ) 0.40 % , d ) 7 % , e ) 40 %
Example Output: d

Example Input: Problem: what is the rate percent when the simple interest on rs . 4000 amount to rs . 320 in 2 years ? 
Options: a ) 4 % , b ) 4.1 % , c ) 4.2 % , d ) 4.3 % , e ) 4.5 %
Example Output: a

Example Input: Problem: rs . 6000 is lent out in two parts . one part is lent at 4 % p . a simple interest and the other is lent at 10 % p . a simple interest . the total interest at the end of one year was rs . 450 . find the ratio of the amounts lent at the lower rate and higher rate of interest ? 
Options: a ) 5 : 1 , b ) 5 : 7 , c ) 5 : 2 , d ) 5 : 8 , e ) 5 : 2
Example Output:
b