Which of the Following Statements About the Fifteenth Century Slave

Which of the following statements about the fifteenth century slave trade is correct?

A) Slavery already existed in West African societies and was a much harsher, less humane form of slavery than that practiced by the Europeans.
B) The only motivation was economic, and race had no role.
C) Slave traders often traded gold for the African slaves.
D) The trade began accidentally because of a linguistic misunderstanding between Portuguese seamen and African tribes.
E) Those sold into slavery by African kings were primarily undesirables such as lawbreakers or persons accused of witchcraft.