Which statement about the Tyndall effect is correct?

1. AIt is shown only by sols whose particles carry an electric charge
2. BIt is due to absorption of light followed by conversion into heat
3. CIt is shown most strongly by true solutions of electrolytes
4. DIt requires the size of the dispersed particles to be not much smaller than the wavelength of light and a noticeable difference between the refractive indices of the two phases