3 light refracts when:\na it changes speed\nb it changes from a particle to a wave\nc its density changes\nd…

3 light refracts when:\na it changes speed\nb it changes from a particle to a wave\nc its density changes\nd it encounters a solid object
Answer
Brief Explanations:
Refraction of light occurs when light passes from one medium to another and its speed changes. Light is both a particle (photon) and a wave (electromagnetic wave) - it doesn't "change" from one to the other in refraction. Density of light isn't a relevant concept here. Encountering a solid object would be more related to reflection (if it bounces off) rather than refraction.
Answer:
A. It changes speed