What point in this body of water is most likely to be the aphotic zone?

The point in this body of water that is most likely to be the aphotic zone is the deepest point. The aphotic zone is the layer of water in which there is not enough light for photosynthesis to occur. As the depth of the body of water increases, so does the amount of water above the point in quesiton. This deeper and deeper column of water reduces the amount of light that can penetrate to its lower reaches.