Which of the following reversible reactions of carbon dioxide explains how hemoglobin serves as a transporter of carbon dioxide?

A)reaction with the imidazole group of the distal histidine where oxygen would normally be bound
B)reaction with the carboxyl group of glutamic acid to form a carbonic acid anhydride
C)reaction with the N-terminal amino groups to form a carbamate
D)reaction with the hydroxyl group of serine to form a carbonate
E)none of the above