The natural advantage that the kingdoms of West Africa have are an abundance of natural resources including salt and gold. The correct option among all the options given in the question is option "b". The Trans-Saharan desert trade route was vital for the economy of that region. The exchange of gold for salt was the mainstay of trade in this region. This was a natural advantage that the kingdoms of West Africa had. The trade route was very vital for the economy of this region.
