A Beam of Light in Air Is Incident at an Angle

Multiple Choice

A beam of light in air is incident at an angle of 30 $\degree$ to the surface of a rectangular block of clear plastic (n = 1.46) .The light beam first passes through the block and re-emerges from the opposite side into air at what angle to the normal to that surface?

A) 42 $\degree$
B) 23 $\degree$
C) 30 $\degree$
D) 59 $\degree$