When the angle of incidence on a material is ${60}^{\circ },$ the reflected light is completely polarized. The velocity of the refracted ray inside the material is $\left(\mathrm{in} {\mathrm{ms}}^{-1}\right)$

• A

  $3\times {10}^8$

• B

  $\left(\frac{3}{\sqrt{2}}\right)\times {10}^8$

• C

  $\sqrt{3}\times {10}^8$

• D

  $0.5\times {10}^8$