The correct option is D DOOD
Diffusion is the process of movement of molecules from a region of higher concentration to a region of lower concentration. Osmosis is a special kind of diffusion. It is the process of movement of water molecules from a region of higher concentration to a region of lower concentration through a semipermeable membrane.
Gas exchange and spreading of molecules in a room take place through diffusion while movement of water molecules inside and outside of a cell is an example of osmosis.