Final answer:
The Roman Emperors were able to rule a vast empire by utilizing a decentralized system of governance, which allowed for local autonomy while maintaining imperial oversight. Strategies for managing the military and local cultures, along with legal and societal reforms, played vital roles in the empire's stability and success. Hence, the correct answer is option (C).
Step-by-step explanation:
One way that the Roman Emperors were able to rule over such a large empire was through a decentralized system of governance. The Roman Empire was divided into provinces each governed by a magistrate, allowing for a degree of local autonomy while maintaining imperial control. This system, along with strategies such as the division of enemies, negotiation from strength, the establishment of colonies, and the spread of Roman culture and infrastructure, helped manage the vast territories and diverse cultures within the empire.
The military, though essential in conflict periods and securing borders, was only a part of Rome's success. The empire's stability was also due to its approach to governance and ability to adapt. For instance, laws like the Theodosian Code centralized legal authority while respecting local traditions, furthering the empire's cohesion.
Roman society's structure, with the Senate developing policies and the emperors such as Augustus and Diocletian enacting reforms, was crucial in navigating challenges like economic issues and external threats.