What is a polis?

A.

a city-state run by kings

B.

the head of a Greek city's government

C.

an elected official in the Athenian assembly

D.

a small state run by citizens

A.?

Polis literally means "city" in Greek. Also, polis is a city state in ancient Greece, especially as considered in its ideal form for philosophical purposes. (City-state) So D is out.

There are still some city-states in the world today, like Monaco or Luxembourg. I think that's a polis.

So it's most likely A.