A light beam is being reflected by using two mirrors, as in a periscope used in submarines. If one of the mirrors rotates by an angle $\mathrm{\theta }$, the reflected light will deviate from its original path by the angle 

• A

  2$\mathrm{\theta }$

• B

  0°

• C

  $\mathrm{\theta }$

• D

  $4\mathrm{\theta }$