Many Butterflies in the Genus Heliconius Are Mimetic, Which Means

Many butterflies in the genus Heliconius are mimetic, which means that they closely mimic the wing patterning and color of highly poisonous species even though they themselves are not poisonous. This is a benefit because many predators (such as birds) learn to avoid poisonous species by identifying their wing patterns and colors. Some closely related Heliconius species mimic different poisonous species. Although they can successfully hybridize and produce viable/fertile offspring that have high fitness in the laboratory, the hybrids are intermediate in wing patterning and color and are not good mimics. Consequently, they have low fitness in nature. This is an example of

A) intrinsic postzygotic isolation.
B) extrinsic postzygotic isolation.
C) habitat isolation.
D) prezygotic isolation.