The answer is option B or a "empire." A empire is made up of many different territories but all under a single rule or king. A city-state are both one territory although states have similar laws some things are legalized in one state but illegal in others. A civilization means a advanced state of human society which doesn't infer to land but to things like science, and technology during a time period. Finally, a city is only one piece of a territory within that territory, which means your answer is in fact B.
