Which of the following are based on Tyndall effect?

The appropriate choices are
Comet's tail in A, sky in B, and clouds in C.

It's known as the Tyndall effect when colloidal particles scatter light.

Because the tiny solid particles the comet leaves in its wake deflect light, the tail of a comet appears as a Tyndall cone.

The Rayleigh scattering phenomenon, rather than the Tyndall effect, is what causes the sky to seem blue because air molecules that scatter light have shorter wavelengths than visible light.