The triangular face of a crown glass prism ABC is isosceles with $$AB=AC$$. The rectangular face with edge AC is silvered. A ray is incident normally on the rectangular face with edge AB, reflects internally at AC and AB, and emerges normally through the rectangular base with edge BC. The angle BAC is

A

$$24^\circ$$

B

$$30^\circ$$

C

$$36^\circ$$

D

$$42^\circ$$