Osmosis is a special kind of diffusion where solvent particles move through a semi permeable membrane from low concentration of solute to high concentration of solute.
so it depends upon
a) how much solvent is present : More the solvent on one side of semipermeable membrane more the movement of solvent particles on the other side of membrane
I think it's B. Molecules collide more frequently
Wow thats pretty hard its asking how many is in each of those