Which agent of erosion is most likely responsible for the deposition of sandbars along ocean shorelines?

The answer is "wave action".

The procedure known as weathering separates shakes with the goal that they can be diverted by the procedure known as erosion. Water, wind, ice, and waves are the agents of erosion that wear away at the surface of the Earth. Waves in seas and other huge waterways deliver coastal erosion. The energy of waves of ocean is magnificent, vast tempest waves can create 2000 pounds of weight or pressure for every square foot.