Final answer:
Option (B), In 509 B.C., the Romans overthrew their king, creating the Roman Republic. Social strife and political struggles eventually contributed to the rise of strong military leaders, setting the stage for the Republic's fall. Octavian, later Augustus, replaced the Republic with the Roman Empire in 27 B.C.
Step-by-step explanation:
In 509 B.C., the Romans overthrew their king and set up a republic, thus establishing a new form of government where citizens would elect their officials. This event marked the transition from monarchy to the Roman Republic structure. However, over time, social issues and the resultant class struggles created deep political rifts within the Republic, eventually leading to the rise of powerful military leaders like Sulla, who marched on Rome to hold power for his fraction.
The misuse of the dictatorship position by such leaders ultimately laid the groundwork for the end of the Republic. It was Octavian, known also as Augustus, who in 27 B.C.E. effectively ended the Republic, establishing the Roman Empire while maintaining the facade of the Republic's survival.