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: the value of a machine depreciates at the rate of 10 % every year . it was purchased 3 years ago . if its present value is rs 8,748 , its purchase price was ? 
Options: a ) rs 16,000 , b ) rs 18,000 , c ) rs 12,000 , d ) rs 14,000 , e ) none of these
Example Output: c

Example Input: Problem: if 40 % of a certain number is 160 , then what is 90 % of that number ? 
Options: a ) 270 , b ) 380 , c ) 260 , d ) 360 , e ) 290
Example Output: d

Example Input: Problem: rs . 2500 is divided into two parts such that if one part be put out at 5 % simple interest and the other at 6 % , the yearly annual income may be rs . 145 . how much was lent at 5 % ? 
Options: a ) 2333 , b ) 2777 , c ) 2688 , d ) 500 , e ) 2871
Example Output:
d