What type of government did all the African empires have ?

All the Kingdoms of of West Africa gained their wealth from the so called Gold salt trade with the Islamic states to the north.

Ghana was the first kingdom of west Africa. Using the technology of storing grain and iron working ,the kingdom gained ascendancy in West Africa. Then with a monopoly with trade to the Islamic states became wealthy. The West African Kingdom would trade gold, ivory and slaves, for salt , manufactured goods, and cloth.

These precious goods from the north would then be traded with other tribes in Western Africa adding to the wealth. The Niger River was instrumental in moving goods within West Africa.

Ghana was replace by Mali as the dominate force in West Africa. Mali continued the same pattern of trade with the Islamic States. One of the kings of Mali Masa Musa ( meaning Great King) even traveled to Mecca bringing immense amounts of gold and slaves to the north

Mali was conquered by the Kingdom of Songhai. This kingdom followed the same pattern of trading gold, ivory and slaves with the north. The Niger River continued to be the main source of trade within Western Africa.

Then the Islamic Kingdom of Morocco decided to cut out the middle man. The Islamic Kingdom of Morocco destroyed the Songhai empire. However the other Western African kingdoms and tribes wouldn't trade with the Moroccans and the Gold Salt trade dissolved.

All three of the Western African kingdoms depended on the Gold Salt trade and control of the Niger River to dominate West Africa.

what are the choices?