The right answer is C. Materials are transported...
Water, the main erosion agent, acts both mechanically and chemically on rocks. It breaks up the softest materials by dripping. The stones shocked against each other break and wear out. The sea, by the repeated shock of the waves, thus fragments the rocks of the littoral. But water also has a chemical action. Indeed, rainwater is concentrated in carbon dioxide when it crosses the atmosphere. They are then able to dissolve certain minerals contained in the rocks.