In the buffer system of nitrous acid (HNO₂) and its salt, NaNO₂, the weak acid (HNO₂) is needed to:
A) Increase the concentration of H₃O⁺ ions
B) Decrease the concentration of H₃O⁺ ions
C) Maintain the concentration of OH⁻ ions
D) Prevent the formation of water (H₂O)
E) Resist changes in pH when bases are added