Consider the following statements about the Tyndall effect:
$(I)$ It is used to distinguish between a true solution and a colloidal solution.
$(II)$ It is possible only when the refractive indices of the dispersed phase and the dispersion medium differ significantly.
$(III)$ It is observed only when the size of the colloidal particles is much smaller than the wavelength of the light used.
Which of the following statements are correct?

• A
  $I$ and $III$ only
• B
  $II$ and $III$ only
• C
  $I$, $II$, and $III$
• D
  $I$ and $II$ only