An isosceles glass prism PQR having refractive index μ has one of its faces PR coated with silver. A ray of light is incident normally on the other face PQ as shown in figure (PQ = PR). The ray of light upon reflection from PR then undergoes TIR at face PQ and finally emerges through the base of the prism perpendicularly. Then angles of prism are :
(A) 40°, 70°, 70°
(B) 50°, 65°, 65°
(C) 36°, 72°, 72°
(D) data insufficient