Which of the following is a reason why the Roman Empire declined?

A.
Economic causes: Opposition to Rome’s policies decreased due to increased military taxes and inflation.

B.
Political causes: Rome’s rulers became less oppressive and less corrupt over time.

C.
Military causes: The military weakened because of the hiring of mercenaries and the invasion of Germanic armies.

D.
Religious causes: The conflict over democratic and republican gods within their mythology caused a civil war.