Answer:
C. the city's overall military strength
Step-by-step explanation:
Athens was the most powerful city-state in Greece during that time. The main trait of Athens is the knowledge, they were the cradle for learning philosophy and arts. It was there that the Aristotle Lyceum was created. This is the main difference from Sparta because Sparta was known for being a military state, most of their spartan spent their time for training and building their military strength, they did not give much attention to education.