Which of the Following Statements About Renal Control of Blood

Which of the following statements about renal control of blood acid-base balance is TRUE?

A) Increased metabolism of glutamine by renal tubular cells increases the plasma bicarbonate concentration.
B) Excretion in the urine of hydrogen bound to phosphate buffers decreases plasma bicarbonate concentration.
C) H⁺ that binds to filtered bicarbonate in the tubular fluid is excreted in the urine.
D) When hypoventilation occurs at the lungs, the kidneys compensate by reducing glutamine metabolism.
E) The kidneys compensate for a metabolic alkalosis by increasing CO₂ production.