The correct answer is option B, that is, Species could go extinct when their environment changed if they could not adapt to the change.
According to Darwin and some of the other scientists who studied the concept of evolution, extinction is usually a result of a change in environmental conditions. When conditions modify, some of the species exhibit adaptations, which permit them to reproduce and survive, while others do not.
If the environment modifies gradually, then the species at certain occasions will develop the essential adaptations, with various generations. If conditions modify more briskly than a species can develop, however, and if the individuals of that species are devoid of the trait, which is required to thrive in the novel surrounding, the probable outcome will be extinction.