Answer:
Correct answer is 4.humans .
Step-by-step explanation:
Last option is the correct one, as we have evidences that the Aztecs sacrificed humans, which of course was not that often among all civilizations. They actually believed that with human sacrifice they would allow humanity to continue living.
We need to know that Aztecs also sacrificed animals, which means that option 3 can also be taken into account, but when compared to other cultures this was not something uncommon.