Answer: 2) Rainsford believes killing humans is murder but has no problem killing animals.
Step-by-step explanation: Based on the given phrase, said by Sanger Rainsford in "The Most Dangerous Game" when he finds out that Zaroff hunts humans, we can infer that Rainsford believes that killing humans is murder but has no problem killing animals, because he says that he is a hunter, not a murderer, this implies that he thinks that killing animals isn't murder. So the correct answer is option 2.