In Systemic Tissue Fluids, the Enzyme Carbonic Anhydrase Catalyzes the Reaction

In systemic tissue fluids, the enzyme carbonic anhydrase catalyzes the reaction CO₂ + H₂O $\rightarrow$ H₂CO₃ (which then can dissociate into H⁺ and HCO₃^-) . In fact, CO₂ released from cells is converted to HCO₃^- ions and travels in that form in the bloodstream. HCO₃^- is reconverted to CO₂ + H₂O in the pulmonary capillaries by the same enzyme, and there the CO₂ is exhaled. How is it possible for the same enzyme to catalyze reverse reactions?

A) The direction of a reversible reaction is influenced by the concentrations of reactants and products. In pulmonary circulation, the low CO₂ concentration favors the formation of CO₂ and H₂O.
B) There must be two forms of carbonic anhydrase. One form catalyzes the forward reaction CO₂ + H₂O $\rightarrow$ H₂CO₃ and the other catalyzes the reverse reaction H₂CO₃ $\rightarrow$ CO₂ + H₂O.
C) The lungs contain an allosteric inhibitor that prevents the formation of carbonic acid.