How Did Contact with the Muslim World Affect the African

How did contact with the Muslim world affect the African slave trade?

A) Because of the Muslim emphasis on equality of all believers, early Muslim rulers suppressed the slave trade.
B) Slavery was unknown in African society until the Muslims introduced it.
C) With the Muslim conquests of north Africa and commercial penetration to the south, slavery became a more widely diffused phenomenon and the slave trade developed rapidly.
D) Despite the Muslim acceptance of slavery and its widespread use in Islamic society outside of Africa, Muslims generally refused to accept black slaves.