The correct answer is "The Aztecs often increased their economy by demanding tribute through payment from conquered peoples".
The basis for economic growth in prehispanic cultures, including the Aztecs, was geopolitical expansion. This was achieved by sending military campaigns to conquer and annex neighboring territories of the Aztec empire. By having a greater tax base to get income from, the empire had more funds in order to make further social developments that would increase the wealth of the empire.
