The main reason why revolution swept so many African nations following their independence from European rule was because there was a giant power vacuum that needed to be filled--usually by a dictator.
The important natural resource in West Africa that the Songhai Empire controlled was salt.
A.) Salt mines in the sahara desert is the answer.
B. Restrain the actions of government against individuals
I think it’s C, because slaves were not allowed to learn to read, so if you had to be literate to vote, most slaves wouldn’t be able to.