Cardinals and blue jays are two species of birds that occupy the same habitat zone and breed the same time of year. which of the following best describes how these two species developed?
a) directional selection
b) temporal isolation
c) stabilizing selection
d) behavioral isolation

The correct option is D.
Behavioral isolation refers to the isolation that occur as a result of reproductive barriers based on behavior. The signals that attract sexual mates to one another is one of the most important determinant factors that determine whether closely related species will be able to mate successfully or not. Behavioral isolation is a type of speciation, which occur when similar species that live in the same environment are unable to mate as a result of differences in sexual behaviors. The sexual behaviors are usually in the form of mating rituals and signals.