Answer:
A) Many African societies, such as the Songhai and the Ashanti, used slave labor
Explanation:
The slavery in Africa was a common thing, and every stronger empire was using labor force. The people that lost in war were taken as slaves, and they were used as free labor force. The Europeans saw the potential of the African slaves for their large plantations in the Americas, so they started to buy them from the African kingdoms, giving them weapons and other goods they needed in return. Quickly the slave trade developed, and the African kingdoms were using the subjucated people to sell them as slaves, so both sides benefited, apart from the slaves of course.