The Experiments with Rats Living in Highly Crowded Cages Suggest

The experiments with rats living in highly crowded cages suggest that

A) overcrowding leads to changes in social behavior among rats.
B) overcrowding leads to short life spans for most rats in crowded conditions.
C) rats become more fertile, thus leading to even more crowded conditions.
D) crowding eventually reduces the population to about a tenth of its original size.