The correct answers are:
a. tribute, or payment;
c. conversion to their religion;
Once a city was conquered by the Aztecs they were immediately setting up their own rules and conditions in order that they keep the city in control, and also that they can benefit from it.
The Aztecs demanded tribute, promise that the people of the city will obey their ruler, and also that they accept and worship their gods. This can be seen from two aspects, one was advantageous in the sense that the Aztecs were able to keep in order the cities and have it their way, and the disadvantageous in the sense that pretty much none of the cities actually liked them, in fact they despised them, which led to a lack of unity in their empire.
