The answer is a large, complex civilization.
This option is incorrect. The Aztec Empire was not small; it was one of the largest and most powerful empires in Mesoamerica before the Spanish conquest. It was also not simple, as it had a sophisticated social, political, and economic structure.
This option is incorrect. While the Aztec civilization was indeed complex, it was not small. The empire covered a vast area of central Mexico and had a large population.
This option is incorrect. Although the Aztec Empire was large, it was not simple. The Aztecs had a highly organized society with a complex system of government, religion, and trade.
This option is correct. The Aztec Empire was large, encompassing much of central Mexico, and it was complex, with an intricate social hierarchy, advanced agricultural practices, and a rich cultural and religious life. The capital city, Tenochtitlan, was one of the largest cities in the world at the time and demonstrated the empire's complexity and sophistication.