Concept:A nation-state is best identified with sovereignty because it describes a state's supreme authority over its own affairs.Explanation:Sovereignty is the absolute power of a state to exercise legal authority within its own territory without external interference.A nation-state is a political entity with a defined geographical territory, a permanent population, and an organized government.Being sovereign means the state is independent and not subject to any outside control in making and enforcing its laws.The concept of a nation-state is therefore directly tied to the possession of sovereignty.Answer:C. sovereignty