Aquaporin has a pair of key asparagine residues located on the wall almost halfway through its pore. These residues simultaneously bind to the oxygen atom of a passing water molecule, rendering it unavailable for hydrogen-bonding. As a result, …

A. the channel can conduct negatively charged (but not positively charged) ions.
B. the channel can conduct glycerol as well as water.
C. the channel cannot conduct glycerol.
D. the channel cannot conduct protons.
E. the channel cannot conduct chloride ions.