Answer: The half reaction that describes the reduction reaction is

Step-by-step explanation:
Oxidation reaction is defined as the reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.

Reduction reaction is defined as the reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.

For the given chemical reaction:

The half reactions follows:
Oxidation half reaction:

Reduction half reaction:

Hence, the half reaction that describes the reduction reaction is
