Who was sold into enslavement after a local or tribal war?

Defeated soldiers

African Warlords

Tribal Chieftains

Slave traders

The correct answer is D (defeated soldier). After a local or tribal war, defeated soldiers were sold into enslavement. What it suggests, is that, slavery had been present in Africa before the Europeans went there. Though it is different than what we usually generalize as "Slavery". Slavery after a tribal war was considered better than European slavery.