The reason for exhibiting the Tyndall effect by colloidal particles is

The size of a colloidal particle is:

Which one of the following statements is $FALSE$ for hydrophilic sols?

$Fe(OH)_3$ sol is:

For $As_2S_3$ sol, the most effective coagulating agent is

The conditions given below are in the context of observing Tyndall effect in colloidal solutions:
$A$. The diameter of the colloidal particles is comparable to the wavelength of light used.
$B$. The diameter of the colloidal particles is much smaller than the wavelength of light used.
$C$. The diameter of the colloidal particles is much larger than the wavelength of light used.
$D$. The refractive indices of the dispersed phase and the dispersion medium are comparable.
$E$. The dispersed phase has a very different refractive index from the dispersion medium.
Choose the most appropriate conditions from the options given below: