Answer:
C
Step-by-step explanation:
The correct answer here would be hybrid sterility.
Postzygotic isolation refers to the mechanisms of reproductive isolation that occur after two organisms of different species have successfully mated and fertilization/formation of zygote has occurred.
Generally, reproductive isolation mechanisms act to prevent members of different species from mating (pre-zygotic)or prevent their products of mating from being viable (postzygotic). A hybrid is a product from mating of two different species of organisms.
The mechanisms of postzygotic isolation include the production of hybrid zygotes that are not viable and hence, will not make it past the embryonic stage or if they do, the resulting offspring remains sterile.
Hence, hybrid sterility is an example of a postzygotic isolation mechanism.