Which of the Following Accounts for the Fluid Aspect of the Fluid

Which of the following accounts for the fluid aspect of the fluid mosaic model of plasma membranes?

A) The individual phospholipid molecules are not bonded to one another, so the movement of certain proteins and lipids is possible within the bilayer.
B) The plasma membrane is "fluid" because of the movement of substances across the membrane.
C) The bilayer permits diffusion of certain lipid-soluble substances.
D) The membrane is water soluble.
E) One of the components of the membrane is water.