The map shows lowlands and highlands of ancient Greece. A map titled Physical Map of Ancient Greece. A key shows Lowlands in green and Highlands in yellow. Thebes, Athens, Corinth, and Sparta are labeled. They are all located in coastal areas with green shading.

Which statement best explains the locations of city-states on the map?

All of the city-states were located on islands.
All of the city-states were located in the lowlands.
All of the city-states were located on mainland Greece.
All of the city-states were located in mountainous areas.