Select the most appropriate word for the given group of words.   A ruler with complete power over a country

Traitor: A traitor refers to a person who betrays their country, organization, or group by acting against it or collaborating with the enemy. Democrat: A democrat is a supporter or advocate of democracy, a system of government in which power is vested in the people and exercised through elected representatives. Aristocrat: An aristocrat refers to a person belonging to the aristocracy, a social class composed of individuals who hold hereditary titles or have a high social rank, typically based on their family background or wealth.