Q. To measure the population density of monarch butterflies occupying a particular park, 100 butterflies arecaptured, marked with a small dot on a wing, and then released. The next day, another 100 butterflies are captured, including the recapture of 20 marked butterflies. One would correctly estimate the population to be.

1. 500
2. 200
3. 1,000
4. 900,000