Final answer:
The Bantu kingdoms of Mapungubwe and Great Zimbabwe had centralized governments, but differed in their economic structures.
Step-by-step explanation:
The Bantu kingdoms of Mapungubwe and Great Zimbabwe were similar to the West African Sahelian kingdoms in terms of their economic structures and their connections to long-distance trade networks. However, there were also some differences between them.
Both the Bantu kingdoms and the Sahelian kingdoms had centralized governments. They both had a political system where a central ruler held power and made important decisions. However, their economic structures differed. The Bantu kingdoms of Mapungubwe and Great Zimbabwe had economies based on agriculture, livestock-keeping, and trade, while the Sahelian kingdoms relied heavily on the trans-Saharan trade routes and control of commodities such as gold, salt, and ivory.
Therefore, the correct answer is a) Both had centralized governments, differing in economic structures.