Answer:
A
Step-by-step explanation:
It says that hippos have been known to cause death in many different ways. So the supporting details should be about the different ways that hippos cause death. Answer D doesn't have anything to do with how hippos are dangerous. Answer C does, but doesn't give us any details other than that. Answer B talks about drowning, but we need to know about the DIFFERENT ways they cause death, not just drowning.
So, A is the most plausible option.