Which of the following is the reason why an aquaporin does not pass ions (such as Na⁺) through?

A) The Na⁺ ions are too small to pass through the pore rapidly enough.
B) The Na⁺ ions are too large to pass through the narrow pore.
C) The Na⁺ ions do not favorably interact with the wall of the pore and therefore cannot be dehydrated.
D) Two Asn residues in the channel prevent the passage of Na⁺ ions.
E) A Na⁺ ion must become fully hydrated to pass through.