Final answer:
The Battle of Thermopylae was C) lost by the Greek forces, but their sacrifice bought time for the Athenians to organize their fleet and eventually defeat the Persian navy at the Battle of Salamis.
Step-by-step explanation:
The outcome of the Battle of Thermopylae was that it was lost by the Greek forces, including a small band of Spartan hoplites led by their king Leonidas. The goal of the Greek forces was not to defeat the invading Persian army, but to delay them so the rest of the forces could organize a defense. The Spartan force fought bravely but was ultimately overwhelmed by the Persians.
For several days, the Greeks successfully held their ground against the Persians, inflicting heavy casualties. However, a local resident named Ephialtes betrayed the Greeks by revealing a mountain path that allowed the Persians to bypass the Greek defenses. However, their sacrifice bought enough time for the Athenians to organize their fleet and eventually defeat the Persian navy at the Battle of Salamis.