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.