In a Battery, the Following Two Oxidation-Reduction Reactions Are Taking

In a battery, the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn+2 + 2e-
Rxn B: 2 NH₄+ + 2e- → 2 NH₃ + H₂
Which reaction is taking place at the anode?

A) rxn A
B) rxn B
C) Both reactions are happening at both the anode and cathode.
D) Both reactions are happening at the electrode.
E) The reaction takes place at the electrode, not the anode.