Answer:
C). Refraction
Step-by-step explanation:
When light enters from one medium to another medium then it changes it's direction from its initial direction
the phenomenon of changing the direction due to change in the medium is known as Refraction of light
So here we know that when light strikes an interface which separates two medium then due to change in the medium we will have

so here we have
= two angles of the light in two mediums
= two refractive index of the two mediums
So correct answer will be
C). Refraction