Hi, there! :)
Answer: (C) Nation-state is the term that best describes the political entity of the Republic of Ireland.
A nation-state is a sovereign state that is inhabited by a particular nation or group of people who share a common:
- culture,
- language,
- or history.
The Republic of Ireland is a sovereign state that is predominantly inhabited by the Irish people, who share a common culture and history, and have their own distinct language, Irish Gaelic.
Hope that helps! Good luck! ^_^