If a Solute Is Moving Through a Phospholipid Bilayer from an Area

If a solute is moving through a phospholipid bilayer from an area of higher concentration to an area of lower concentration without the assistance of a protein,the manner of transport must be

A) active transport.
B) facilitated diffusion.
C) simple diffusion.
D) Any of the presented options,depending on the solute.
E) Solutes cannot cross phospholipid bilayers.