Which of the Following Reactions Illustrate the Reaction of a Base

Which of the following reactions illustrate the reaction of a base? I. NH₃ + H₂O → ⁺NH₄ + ^-OH
II) HCl + H₂O → H₃O⁺ + Cl^-
III) NaOH → Na⁺ + ^-OH
IV) ⁺NH₄ + H₂O → H₃O⁺ + NH₃

A) I only
B) II only
C) I and III
D) I, III, and IV
E) All of the above are reactions of a base.