In ancient Greece, what did the Greek word Polis refer to?

A) The fundamental political unit of ancient Greece controlled by a city-state that usually tended to be a democracy.

B) A large area controlled in World by strong rulers. It was also the fundamental institution in ancient Greece.

C) a form of government called city-state controlled by a group of people called the Philosopher's.

D) an area controlled and ruled by a strong City. It was also the fundamental political unit in ancient Greece. ​