When Santos stands in a swimming pool and looks at his feet, his legs appear to be bent. Which is the term for this phenomenon? A) diffraction B) dispersion C) reflection D) refraction

I would say A sorry if its incorrect

the answer is d because Refraction is the change in direction of propagation of a wave due to a change in its transmission medium. The phenomenon is explained by the conservation of energy and conservation of momentum. Due to change of medium, the phase velocity of the wave is changed but its frequency remains constant.