The process of separation of colloids by passing through a semipermeable membrane is called
filtration
electrophoresis
Dialysis
ultra-filtration
Dialysis: It is the process of removing a dissolved substance from a colloidal solution by means of diffusion through a suitable membrane. Since particles (ions or smaller molecules) in a true solution can pass through the animal membrane (bladder) or parchment paper or cellophane sheet but not the colloidal particles, the membrane can be used for dialysis. The apparatus used for this purpose is called dialyser.
So, Option 3 is correct.