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: if price of t . v set is reduced by 10 % , then its sale increases by 85 % , find net effect on sale value 
Options: a ) 44 , b ) 45 , c ) 46 , d ) 67 , e ) 48
Example Output: d

Example Input: Problem: a sum of money at simple interest amounts to $ 815 in 3 years and to $ 854 in 4 years . the sum is : 
Options: a ) $ 153 , b ) $ 698 , c ) $ 398 , d ) $ 549 , e ) $ 675
Example Output: b

Example Input: Problem: the population of a town is 8000 . it decreases annually at the rate of 30 % p . a . what will be its population after 2 years ? 
Options: a ) 3920 , b ) 5120 , c ) 5200 , d ) 5400 , e ) 5500
Example Output:
a