Why not A

Hello @HannahNg, This is kind of a tricky question. Why did the author discuss the Nile perch? Is the Nile perch an example of an extinct species? No, because it is not extinct! Rather, it was carelessly introduced to a new habitat, where it is a threat to other species. Take a closer look at the sentence starting on line 38. This is still the fault of humans, so B is the correct answer.