Explain how waves and currents are affecting this beach over time

The answer is the Movement of sediments.  Waves and currents affect the movement of sediment.  But changes in sediment levels affect the waves and currents. For example, sand eroded from the beach may move offshore to form a sandbar. That causes waves to break farther offshore, protecting the beach from further erosion.  But shallow sandbars may lead to increased erosion.

The answer would be c