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 reduction of 40 % in the price of bananas would enable a man to obtain 50 more for rs . 40 , what is reduced price per dozen ? 
Options: a ) 1.34 , b ) 2.84 , c ) 3.84 , d ) 4.34 , e ) 5
Example Output: c

Example Input: Problem: of 600 surveyed students , 20 % of those who read book a also read book b and 25 % of those who read book b also read book a . if each student read at least one of the books , what is the difference between the number of students who read only book a and the number of students who read only book b ? 
Options: a ) 20 , b ) 25 , c ) 30 , d ) 35 , e ) 75
Example Output: e

Example Input: Problem: a person lent a certain sum of money at 4 % per annum at simple interest and in 8 years the interest amounted to rs . 306 less than the sum lent . what was the sum lent ? 
Options: a ) 228 , b ) 278 , c ) 289 , d ) 500 , e ) 450
Example Output:
e