A rectangular glass slab ABCD of refractive index `n_1` is immersed in water of refractive index ` n2(n1ltn2)`. A ray of light is incident at the surface AB of the slab as shwon. The maximum value of the angle of incidence `alpha`max such that the ray comes out from the other surface CD is given by
.

Options

A. `sin^(-1 )[(mu_1)/(mu_2) cos(sin^(-1) (mu_2)/(mu_1))]`
B. `sin^(-1)[mu_1 cos(sin^(-1) 1/(mu_2))]`
C. `sn^(-1) (mu_1)/(mu_2)`
D. `sin^(-1) (mu_2)/(mu_1)`.