In an Effort to Measure the Size of a Bluegill

Multiple Choice

In an effort to measure the size of a bluegill population in a pond, you capture 40 bluegills and mark each with a tag on the tail fin and then release them. A week later you return to the pond and catch 40 more, of which 8 have a tag on the tail fin. What is the best estimate of the bluegill population in the pond?

A) 100
B) 160
C) 200
D) 320
E) 400