The option that correctly analyzes how the cartaz system represented a departure from previous patterns of trade is:
**A. Portuguese ports now had exclusive control of Indian Ocean trade.**
The cartaz system, implemented by the Portuguese, required ships to carry a pass (cartaz) issued by the Portuguese authorities to legally trade in the Indian Ocean. This system allowed the Portuguese to exert significant control over maritime trade routes in the region, marking a transition from previous, more decentralized trading practices to a system where Portuguese ports held exclusive power over trade activities.