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: in a certain pond , 40 fish were caught , tagged , and returned to the pond . a few days later , 40 fish were caught again , of which 2 were found to have been tagged . if the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond , what is the approximate number of fish in the pond ? 
Options: a ) 1000 , b ) 625 , c ) 1,250 , d ) 2,500 , e ) 10,000
Example Output: a

Example Input: Problem: during a thanksgiving weekend , a car rental company rented 6 - tenths of their vehicles , including two - fifths of the 4 wds that it had . if 40 % of the vehicles are 4 wds , then what percent of the vehicles that were not rented were not 4 wds ? 
Options: a ) 20 % , b ) 30 % , c ) 40 % , d ) 50 % , e ) 60 %
Example Output: c

Example Input: Problem: there are 500 employees in a room . 99 % are managers . how many managers must leave the room to bring down the percentage of managers to 98 % ? 
Options: a ) 150 , b ) 200 , c ) 250 , d ) 350 , e ) 400
Example Output:
c