Although They Are Smaller Than K⁺,Na⁺ Ions Fail to Pass

Multiple Choice

Although they are smaller than K⁺,Na⁺ ions fail to pass through K⁺ channels because Na⁺

A) is repulsed by positively charged amino acids at the mouth of the channel.
B) is too small to interact with oxygen atoms in amino acids on all sides of the channel and therefore does not completely lose its waters of hydration.
C) is always transported complexes to Cl⁻.
D) is always transported in a complex with two other Na⁺ ions.
E) is attracted by other Na⁺ ions,which are at higher concentration outside than inside the cell.