Task: Question Answering
Input (English): Problem: in a certain pond , 20 fish were caught , tagged , and returned to the pond . a few days later , 20 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 ` s the approximate number of fish in the pond ? 
Options: a ) 400 , b ) 625 , c ) 1250 , d ) 2500 , e ) 500
Output (English): e