Physics

Newton's third law states that for every action, there is an equal and opposite reaction. The action and reaction forces act on different objects.

The situation of the swimmer: The action force is the force exerted by the swimmer on the wall. The reaction force (the equal and opposite force) is the force of the wall pushing back on the swimmer.

Option A

The force of the water pushing forward on the swimmer is a different force that affects the swimmer's forward motion, but it's not the reaction force to the swimmer - wall interaction.

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