Which of These Statements Is True Regarding the Regulation of H⁺

Which of these statements is true regarding the regulation of H⁺ levels in the body by the kidney?

A) H⁺ is secreted by apical membrane of intercalated cells in the collecting duct, and bicarbonate ions cross the basolateral membrane into peritubular capillaries.
B) The level of H⁺ is entirely determined by secretion of H⁺ into and reabsorption of Na⁺ from tubular fluid by cells lining the proximal convoluted tubule
C) H⁺ is secreted by crossing the basolateral membrane of intercalated cells into peritubular capillaries, where the protons can then be excreted from the body in the urine.
D) Excess H⁺ reacts with dihydrogen phosphate in the kidney to form monohydrogen phosphate, thus buffering the pH in body fluids.
E) The kidney does not play a role in regulation of pH; exhalation of carbon dioxide in the lungs is the only way that the body regulates pH of body fluids.