Which one of the following reactions is a redox reaction?
A) H₂O + NaCl - NaOH + HCl
B) NaOH + HCl - NaCl + H₂O
C) Pb²⁺ + 2Cl⁻ - PbCl₂
D) AgNO₃ + HCl - HNO₃ + AgCl
E) None of the above is a redox reaction.