One of the Buffers That Contribute to PH Stability in Human

One of the buffers that contribute to pH stability in human blood is carbonic acid (H₂CO₃) . Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO₃⁻) and a hydrogen ion (H⁺) . (See figure.)

If the pH of blood drops, one would expect ________.

A) a decrease in the concentration of H₂CO₃ and an increase in the concentration of HCO₃⁻
B) the concentration of bicarbonate ions (HCO₃⁻) to increase
C) the HCO₃⁻ to act as a base and remove excess H⁺ by the formation of H₂CO₃
D) the HCO₃⁻ to act as an acid and remove excess H⁺ by the formation of H₂CO₃