Channel Proteins in Cell Membranes Serve What Function

Channel proteins in cell membranes serve what function?

A) They add strength and rigidity to the membrane.
B) They provide pathways for water and electrolytes to move through cell membranes.
C) They form the bilayer portion of the membrane.
D) They prevent interactions between the nonpolar tails of the phospholipids which gives the membrane its fluidity.
E) They allow nonpolar substances to move through the membrane.