The correct answer is B) an empire.
An empire is the name for a geographically wide-ranging group of people and states ruled by a single government.
During the history of humanity, many territories have been ruled by emperors. An empire can be understood as a group of states ruled by one governor or king. The empire encompassed many people, towns, cities in different territories. The best example to understand the concept of an empire was the powerful Roman Empire that in its times owned one-third of the known world. Other important empires were the Byzantine Empire or the Ottoman Empire.