Concept:Hydraulic action is a wave process that causes erosion of coastal rocks.
Explanation:In hydraulic action, the force of waves forces air into cracks and crevices in rocks.
This compressed air exerts pressure and weakens the rock.
Over time, the repeated pressure causes the rocks to break apart.
This breakdown of rock material is a clear example of erosion.
Traction, saltation, and suspension are all methods of transporting eroded sediment.
These transport processes move material but do not erode the coastline themselves.
Therefore, the only erosion process among the given options is hydraulic action.
Answer:B. hydraulic