When the angle of incidence on a material is `60^(@)`, the reflected light is completely polarised. The velocity of the refracted ray inside the materials is (in m//sec^(-1))

A. `3xx10^(8)`

B. `(3/sqrt(2))xx10^(8)`

C. `sqrt(3)xx10^(8)`

D. `0.5xx10^(8)`