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: rs . 1500 is divided into two parts such that if one part is invested at 6 % and the other at 5 % the whole annual interest from both the sum is rs . 86 . how much was lent at 5 % ?
Options: a ) 388 , b ) 2998 , c ) 277 , d ) 500 , e ) 400
Example Output: e

Example Input: Problem: if the simple interest on a certain sum of money for 5 years is one fifth of the sum , then the rate of interest per annum is
Options: a ) 4 % , b ) 7 % , c ) 6 % , d ) 4 % , e ) 3 %
Example Output: d

Example Input: Problem: the area of a circle is increased by 800 % . by what percent has the radius of the circle increased ?
Options: a ) 100 % , b ) 400 % , c ) 300 % , d ) 600 % , e ) 200 %
Example Output:
e