Unpolarised light is incident from air on a plane surface of a material of refractive index $\mu$. At a particular angle of incidence $i$,it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation?

• A
  Reflected light is polarised with its electric vector parallel to the plane of incidence
• B
  Reflected light is polarised with its electric vector perpendicular to the plane of incidence
• C
  $i = \tan^{-1}(1/\mu)$
• D
  $i = \sin^{-1}(1/\mu)$