Why Was Florence Considered the Preeminent Italian City-State of the Fifteenth

Why was Florence considered the preeminent Italian city-state of the fifteenth century?

A) Florence was home to the Medicis, a wealthy and powerful family who supported the city's guilds and artists and influenced the city's politics.
B) Florence was a premier city for religious response to social unrest.
C) Florence was known for ceramics and pottery, a growing industry with merchants of the rising middle class.
D) Florence was favored by Pope Eugenius IV, who conducted ordinations in St. Mark's Square.