We know that the refractive index of the material \(n=\frac{c}{v};\) where is the velocity of light. Refractive index shows the material’s bending power of light. Hence for same value of angle of incidence the material in which angles of refraction is minimum that would have greatest refractive index \((n=\frac{sin\,i}{sin\,r})\). So, A has maximum refractive index and hence velocity of light is minimum in it.
