What made florence thrive financially? (site 1)

Florence became financially wealth because of its city-state.

Explanation:

Florence began to flourish from late middle ages to the renaissance period. It became a significant city in Italy because of its geographical condition that made the region a perfect place for coastal trade. Florence recognized as one of the most prominent cities of economic, cultural, political, social, and artistic centers in Italy. Families like Medici (bankers) became patrons for painters, philosophers, and architects in Italy during the Renaissance period. Florence maintains industry in silk, wood and created banks for loans.    

d. china

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d is the best choice