Several species of leopard frogs are common throughout North America, where their ranges overlap. Different species of leopard frogs are very similar in appearance, but the males of each species have a unique courtship call. How did speciation most likely occur in leopard frogs?

A. Reproductive isolation occurred through behavioral isolation.
B. Reproductive isolation occurred through temporal isolation.
C. Populations were separated through geographical isolation.
D. Populations were separated through competition.

Speciation is a process of development of new species from the previously existing species due to reproductive barriers occur among the members of the population of species. The reproductive barrier arises due to behavior and physical differences. Behavior isolation occurs when the two populations of the same species develop some differences in behavior, to attract their mates for mating, which can lead to reproductive isolation among members of same species or related species.

In the given situation, the related species of leopard frogs have developed specific courtship call, this will lead to reproductive isolation due to behavior isolation. This will help in identifying mates of the same species and this will act as a reproductive barrier among the other related species.