Which mineral did people in Central Africa use to make better tools 3,000 years ago? A. Iron
B. Salt
C. CoBalt
D. Limestone

I think it's A.(Iron) Based on my research,iron played a central role in many societies of early Africa. It held both spiritual and material power. Physically, Africans used iron to create tools for agriculture, utensils for everyday life, and weapons for protection and conquest. So basically the use of iron ushered in an iron age in Africa, with the expansion of agriculture, industry, trade, and political power.