Concept:Coastal erosion is primarily controlled by wave action along the shore.Explanation:The intensity of coastal erosion is determined by the energy, height, and type of waves that reach the coast.Powerful, high-energy waves erode the coastline more rapidly.Gentle, low-energy waves tend to deposit sand and sediments instead of eroding.Factors like ocean depth and salinity only influence waves indirectly.The direct controlling factor is the nature of the waves themselves.Answer:D. Nature of the waves