What was the main cause of the Peloponnesian War?



A.

The Spartans resented Athens' dominance over other city-states.



B.

The Peloponnesian people turned out to be even fiercer warriors than the Spartans, so they attacked.



C.

Sparta began building a navy and the Athenians responded.



D.

The other city-states decided to band together to defeat Sparta and Athens.