Which of the Following Statements Is (Are)true Concerning Passage Across

Which of the following statements is (are) true concerning passage across body membranes?

A) The membrane lipids make the membrane relatively permeable to ions and polar molecules.
B) The lipid molecules orient themselves so that they form a fluid bimolecular leaflet structure with the hydrophobic ends of the molecules shielded from the surrounding aqueous environment.
C) Membrane carbohydrates make up the structural components of the membrane and help move the molecules across the membrane during the transport process.
D) Both a and b are true.
E) Both b and c are true.