Which,if Any,of the Following Aqueous Mixtures Would Be a Buffer

Multiple Choice

Which,if any,of the following aqueous mixtures would be a buffer system?

A) CH₃COOH,NaH₂PO₄
B) H₂CO₃,HCO₃^-
C) H₂PO₄^-,HCO₃^-
D) HSO₄^-,HSO₃^-
E) None of these will be a buffer solution.