When Blood Starts to Become Too Acidic, the Kidneys Respond

When blood starts to become too acidic, the kidneys respond by

A) synthesizing and secreting bicarbonate ions while reabsorbing H⁺.
B) synthesizing and reabsorbing H⁺ while filtering bicarbonate ions.
C) synthesizing and reabsorbing bicarbonate ions while secreting H⁺.
D) decreasing filtration rate and increasing reabsorption of both bicarbonate ions and H⁺.
E) increasing filtration rate and increasing reabsorption of H⁺.