Which Reaction Is Not an Example of a Redox Reaction

Which reaction is not an example of a redox reaction?

A) 2 Hg(l) + O₂(g) → 2 HgO(s)
B) 2 (NH₄) ₃PO₄(aq) + 3 Ba(NO₃) ₂(aq) → Ba₃(PO₄) ₂(s) + 6 NH₄NO₃(aq)
C) CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(g)
D) 6 HCl(aq) + 2 Al(s) → 2 AlCl₃(aq) + 3 H₂(g)
E) 2 Al₂O₃(s) → 4 Al(s) + 3 O(g)