Answer:
B. trade
Step-by-step explanation:
According to a different source, the options that are included in this question are:
A. religion
B. trade
C. agriculture
D. politics
Trade is the main reason why many towns and cities developed in Sub-Saharan Africa during the 11th century through the 15th century. During this time period, trade in this region became very important. Goods such as salt and gold travelled through sub-Saharan Africa all the way to North Africa, and from there to Europe and Asia. This also led to the rise of various African empires.