The Main Intracellular Buffer System Is

The main intracellular buffer system is

A) H₃PO₄\H₂PO₄ ⁻
B) H₂PO₄ ⁻ \ HPO₄^{2 −}
C) HPO₄^{2 −} \PO₄^{3 −}
D) H₃PO₄\PO₄^{3 −}