Thanks for the question! We’re told here that some animals don’t tolerate attacks on other wolves if those wolves have submitted. The philosopher then concludes that it’s wrong to deny that animals have rights if the reasoning is that only human beings can obey moral rules.
Now, let’s take a look at (C). (C) tells us that the philosopher tries to cast doubt on the principle that being capable of obeying moral rules is a necessary condition for having rights. But that’s not exactly what’s going on here. It could still be possible that being able to obey moral rules is a necessary condition to have rights. What the author is trying to show is that some animals do have this condition, so even if it were a necessary condition, then animals shouldn’t be denied rights based on the lack of this necessary condition.
Hope this helps. Feel free to ask any further questions that you might have.