Which of the following describes the lining of the channel within maltoporin?

a. A series of aromatic side chains arrange in a helical pattern matching the relative curvature of the protein backbone, thus provided little restriction to transport.
b. Hydroxyl groups on glucose hydrogen bond with polar and charged side chains lining the channel, thus resulting in a series of interactions mimicking a screw-like pathway.
c. There is a pathway of phospholipids that line the inside of the channel and facilitate transport.
d. Constriction in the channel removes waters of hydration, thus making the substrate more hydrophobic and "greasy."