Ineed figuring out which one it is

Based on my research Diffusion is the answer here because it is part of osmosis and it happens when molecules can pass through a permeable membrane through a smaller space then spreads out to a larger space.

active transport is the movement of atomic substances across a cell membrane with the help of energy and enzymes.

Passive transport is the movement of atomic substances across cell membranes without the help of any force or energy.

Selectively permeable membrane is a type of membrane that allows selected molecules or atomic substances to enter the membrane from where osmosis can happen.