When light travels from an optically denser to a rarer media, it is partially refracted to the rarer medium and partially reflected back into the optically denser medium at the interface. Total internal reflection is the name given to this kind of reflection. The light beam deviates from the normal as it moves from a denser medium to a rarer media at the interface during refraction.

When a propagating wave encounters a medium barrier at an angle greater than a specific critical angle with respect to the surface normal, the phenomenon known as total internal reflection occurs. The wave cannot travel through and is completely reflected if the refractive index is lower on the opposing side of the barrier and the incidence angle is larger than the critical angle. The incidence angle above which 100% internal reflection takes place is known as the critical angle.

Hence, the correct answer is option B.