The correct answer is D. Two species of insects produce infertile offspring
Explanation:
In biology, the prezygotic barrier refers to mechanisms or barriers that avoid different species to reproduce or that occur before a zygote is formed, this includes differences in the geographical location or ecosystem species reproduce, the time in which they reproduce, reproduction rituals, among others. Additionally, prezygotic barriers differ from postzygotic because postzygotic barriers occur after the zygote has formed and this mainly includes offspring that has lower viability or that is infertile. Considering this, the one that is not an example fo a prezygotic barrier is "Two species of insects produce infertile offspring" because different to the rest of the examples, this occurs after the zygote forms and therefore is a postzygotic barrier and not prezygotic.