Here osmosis is best defined as the movement of SO. Remember osmosis is the movement of a solvent across a semi permeable membrane. Our solvent typically is water, so it's a movement of water molecules.
So that means B&C are out and let's see across a semi permeable membrane into a region of low solute concentration. No, not low high. Because of that A can't be the answer.
Therefore D is the correct one where water molecules move across a semi membrane into a region of high solute concentration. So here option D would be the correct answer.