Membrane Proteins Are Found

Membrane proteins are found

A) as distinct layers with one layer facing the extracellular fluid and the other facing the intracellular fluid.
B) both embedded in and associated with the lipid bilayer of the plasma membrane.
C) associated with the lipid bilayer of the plasma membrane, but not actually embedded in it.
D) only in the plasma membrane, and not in other cellular membranes.
E) none of these.