How did geography most benefit the Malacca and Brunei sultanates?

A: They depended on natural barriers like mountains to protect them from invasion.
B: They used overland access to India and China to develop profitable trade relations
C: They spread out across many islands, making it difficult for other peoples to conquer and control them.
D: They relied on waterways like the Strait of Malacca to control important sea trade routes.

D: They relied on waterways like the Strait of Malacca to control important sea trade routes.