Petrie (1994) Paired Each of Several Peacocks with Four Peahens

Petrie (1994) paired each of several peacocks with four peahens, chosen randomly, in a laboratory. The peacocks varied in terms of the number of eye-spots on their trains. All the offspring were raised under common conditions. When the offspring were 84 days old, the offspring of the males with more elaborate trains weighed more than the offspring of those with less elaborate trains. This difference in offspring viability cannot be due to differences in the quality of the females because the

A) matings were arranged arbitrarily by the experimenter.
B) peacocks rejected any females that weren't of sufficient quality.
C) quality of the females across groups was uniformly high.
D) quality of the females across groups was uniformly low.