The correct answer is B. Kerr effects.
Kerr effects are nonlinear effects in optics that are defined by the intensity-dependent refractive index of the fiber. This means that the refractive index of the fiber changes depending on the intensity of the light that is passing through it. This can lead to a number of different effects, such as self-focusing and self-modulation.
Scattering effects are caused by the interaction of light with the material of the fiber. This can lead to a loss of light as it travels through the fiber.
Raman effects are caused by the interaction of light with the molecules of the fiber. This can lead to a change in the wavelength of the light as it travels through the fiber.
Tomlinson effects are caused by the interaction of light with the electrons of the fiber. This can lead to a change in the frequency of the light as it travels through the fiber.