Concept:Salt was a vital trade good in West Africa because it preserved food and replaced scarce minerals in the diet.
Explanation:Long before 1800, salt was one of the most valuable commodities in the Nigeria area.
It was scarce in the forest and coastal regions, so communities depended on supplies from Saharan salt mines.
Merchants exchanged salt for gold, slaves, and agricultural products across trans-Saharan trade routes.
This active salt trade created wealth and strengthened many powerful states and trading centres in the region.
Because it was so widely accepted, salt also acted as a medium of exchange in several West African markets.
Therefore, the commodity most responsible for the commercial rise of many Nigerian states was salt.
Answer:D. Salt