Concept:High population density in some regions is due to fertile land and agricultural opportunities.Explanation:The Ruhr and the Midlands of England have high population density due to industrialisation and coal mining.The Amazon Basin has low population density because of dense rainforest and poor soils.The Nile Basin supports intensive agriculture through irrigation along the River Nile, leading to high population density in an otherwise dry region.Answer:B. The Nile Basin