Task: Question Answering
Input (English): Problem: in a certain pond , 30 fish were caught , tagged , and returned to the pond . a few days later , 50 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 ) 750 , b ) 625 , c ) 1,250 , d ) 2,500 , e ) 10,000
Output (English): a