# The angle of incidence for a ray of light at a refracting surface of a prism is $45^o$. The angle of prism is $60^o$. If the ray suffers minimum deviation through the prism, the angle of minimum deviation and refractive index of the material of the prism respectively, are :
( A ) $30^o; \sqrt{2}$
( B ) $30^o; \frac{1}{\sqrt{2}}$
( C ) $45^o; \frac{1}{\sqrt{2}}$
( D ) $45^o; \sqrt{2}$