The correct response is: Portuguese ports now had exclusive control of Indian Ocean trade.
Explanation:
The cartaz system, implemented by the Portuguese in the 16th century, marked a significant departure from previous trade practices in the Indian Ocean. Traditionally, trade in the region was dominated by a variety of players, including local merchants, Muslim traders, and Venetian traders, who operated in a more competitive and decentralized manner. With the introduction of the cartaz, which was essentially a permit required for ships to trade in the area, the Portuguese established a measure of control over maritime trade routes.
Unlike previous systems where multiple powers operated independently, the cartaz system allowed the Portuguese to manage and regulate trade more effectively, leading to greater dominance and the monopolization of key trading ports in the Indian Ocean. While it didn't completely eliminate competition from other traders, it did significantly alter the balance of power in favor of the Portuguese and diminished the influence of other trading groups, thereby granting them a more exclusive control over trade in the region.
The other options do not capture the essence of how the cartaz system represented a major shift in trade dynamics. The claim that it made few long-lasting changes underplays its significant impact, while the alliances suggested in the other responses didn't materialize in the way implied, as the Portuguese primarily sought to assert their dominance rather than form lasting alliances with competitors.