The correct answer is: B. total internal reflection.
Total internal reflection is the optical phenomenon that occurs when light passes from a medium with a higher refractive index to a medium with a lower refractive index, and the angle of incidence is greater than the critical angle. At the critical angle, the light is refracted at an angle of 90 degrees to the normal, and no light is transmitted into the second medium.
Optical fibers work on the principle of total internal reflection. The light is guided down the fiber by repeated total internal reflections at the interface between the core and the cladding. The core has a higher refractive index than the cladding, so the light is always refracted back into the core.
Scattering is the phenomenon that occurs when light is scattered in all directions by particles of a much smaller wavelength. This can happen when light passes through a medium with many small particles, such as air or water. The light is scattered in all directions by the particles, and this is why we see things like clouds and the sky.
Interference is the phenomenon that occurs when two waves of light meet and interact with each other. This can happen when light passes through a medium with two different refractive indices, such as a thin film. The light waves interfere with each other, and this can cause the light to be either amplified or cancelled out.
I hope this helps! Let me know if you have any other questions.