The correct analysis of how the cartaz system represented a departure from previous patterns of trade is:
Portuguese ports now had exclusive control of Indian Ocean trade.
The cartaz system, instituted by the Portuguese in the early 16th century, required ships to obtain a pass (cartaz) in order to trade in the Indian Ocean. This system allowed the Portuguese to exert control over maritime trade routes and assert dominance over other trading powers, marking a significant shift from earlier, more open trading practices.