Have you ever heard about Louis and Clark and Sacagawea? Anywho after the territory was bought from France Jefferson, the president at the time, sent a group of men to explore the territory. They were led by Louis and Clark, they met an Indian tribe and an Indian woman helped them on their journey.
From what i can actually read it look to be correct.
A. Mali because Mansa Musa was the conqueror of the Mali empire
D all 3 of them would be causes