I think a would be the best answer for the preposition
I would say that the correct answer would be "Definition", as the passage is defining Americans' respect, or lack thereof, for Native culture.
Answer:
The reign of Augustus from 27 BCE to 14 CE brought peace and security to both politics and trade. The Roman Senate granted Augustus almost unlimited powers, bringing reform to both the city and provinces. He became the “first citizen” or princeps, thus initiating the principate.
I don't really get it so yeah