A transparent solid cylindrical rod has a refractive index of `(2)/(sqrt3`) .It is surrounded by air. A light ray is incident at the mid-point of one end of the rod as shown in the figure. The incident angle theta for which the light ray grazes along the wall of the rod is:

Options

A. `sin−1(3–√2)`
B. `sin ^(-1)(sqrt3//2)`
C. `sin^(-1) (1//sqrt3)`
D. `sin^(-1) (2//sqrt3)`.