The H⁺ Secreted into the Tubular Fluid of the Late

The H⁺ secreted into the tubular fluid of the late distal tubule and collecting duct are buffered by

A) NH₃ and HCO₃⁻
B) NH₃ and HPO₄²⁻
C) HCO₃⁻ and H₂PO₄^-
D) HPO₄²⁻ and NH₄⁺
E) H₂PO₄⁻ and HPO₄²⁻