Answer:d. the defeat of the Persians in 480 BCE.
Explanation:The Early Classical period, also called the Period of Transition, lasted from c. 480-450 BCE. [1] It was the transitional period between the Archaic period and the High Classical period. Throughout the Classical period, the Greeks were interested in humanism, rationalism, and idealism.
Battle of Thermopylae, (480 bce), battle in central Greece at the mountain pass of Thermopylae during the Persian Wars. The Greek forces, mostly Spartan, were led by Leonidas. ... Sending the main army in retreat, Leonidas and a small contingent remained behind to resist the advance and were defeated.
Sectionalism. Sectionalism is loyalty to one's own region or section of the country, rather than to the country as a whole.
The rise of the public sphere and public opinion.
The growth of a print culture and literary market - newspapers etc, the multiplier effect.
The rise of coffee houses, clubs, social gatherings. The voice of the street
The breakdown of absolutist politics.