Which of the Answers Below Is INCORRECT for Diprotic Acids

Which of the answers below is INCORRECT for diprotic acids and bases?

A) Solutions of H₂A are treated as monoprotic to calculate [H⁺],[HA⁻] and [H₂A].
B) The pH for HA⁻ solutions is appro×imated with pH = ½(pK₁ + pK₂) .
C) K_a1K_b1 = K_w and K_a2K_b2 = K_w
D) Solutions of A²⁻ is treated as monobasic to calculate [OH⁻],[HA⁻],and [A²⁻].
E) A zwitterion is a neutral molecule with both positive and negative charges.