When a swimmer goes deeper into the swimming pool, the temperature of water decreases. As a result, the speed of sound will

Explanation

The correct answer is that the speed of sound will decrease as a swimmer goes deeper, where the water temperature is lower. Sound travels faster in warmer temperatures because the molecules in the medium are more active and transfer the sound waves more quickly. Conversely, in colder temperatures, the molecules are less active, leading to a slower speed of sound. Therefore, options A and D are incorrect because they suggest that the speed of sound would increase or remain the same, respectively, which does not align with the physics of sound propagation in different temperatures. Option C is incorrect as sound will not become zero; it simply travels slower in colder temperatures.