Correct Response: C. Longshore currents that transport sand grains and other sediments along the immediate coastline are driven by the waves striking the shore at an angle. When a wave reaches a beach or coastline, it releases a burst of energy that generates a current, which runs parallel to the shoreline. This type of current is called a longshore current. Tidal forces that affect local sea level are not a primary factor driving longshore currents (A) and while prevailing winds (B) do produce the waves, they do not release the energy that generates the current. Beach runoff or backwash (D) is a source of sediment for longshore drift (the movement of sediment down the shoreline), but is not the source of energy for longshore currents.
