Which of the Following Ammonium Salts Would Be Considered an Acidic

Which of the following ammonium salts would be considered an acidic salt when dissolved in water?
I. (NH₄) (CH₃COO) K _a(CH₃COOH) = 1.8×10 ^{- 5} K _b(NH₃) = 1.8×10 ^{- 5}
II. NH₄CN K _a(HCN) = 6.2×10 ^{- 10} K _b(NH₃) = 1.8×10 ^{- 5}
III. NH₄Cl

A) All ammonium salts are acidic
B) All ammonium salts are basic
C) III only
D) I and II
E) II and III