What is the best explanation for the spread of the Renaissance to northern Europe?

Question

Responses

Italian armies conquered large areas of Europe.
Italian armies conquered large areas of Europe.

Italian merchants traded with prosperous cities to the north.
Italian merchants traded with prosperous cities to the north.

Traders from the Byzantine Empire arrived in European cities.
Traders from the Byzantine Empire arrived in European cities.

Artists and thinkers fled Italy because of war and disease.

Answer 1

Italian merchants traded with prosperous cities to the north.