The answer should be A. They were overproducing goods.
Preemption
This doctrine is centered around the attempt to repel or defeat a perceived imminent offensive or invasion. The aim is to gain a strategic advantage in an impending (allegedly unavoidable) conflict shortly before it materializes into a crisis. Its principles include unilateralism and the use of preventative war.
Well, the Lydenburg heads are seven terracotta heads that were found(among other pottery artifacts) in Lydenburg, Mpumalanga, South Africa. They are from the Iron Age. They can be linked to several tribes across the continent, some of which include: The Bantu, The Ndebele, and The Bini. I hope this helped you with your question!