Visible light travels more slowly through an optically dense medium than through a vacuum. A possible explanation for this could be that the light: A is absorbed and re-emitted by the atomic structure of the optically dense medium. B is absorbed and re-emitted by the nucleus of the material in the optically dense medium. C bounces around randomly inside of the optically dense medium before emerging. D loses amplitude as it passes through the optically dense medium. Solution: The correct answer is A.