Consider the redox reaction below.

Answer : The correct option is,

Explanation :

Redox reaction or Oxidation-reduction reaction is the reaction in which the oxidation and reduction reaction takes place simultaneously.

Reduction reaction : The reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

Oxidation reaction : The reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

The given balanced chemical reaction is :

The oxidation-reduction half reaction will be :

Oxidation :

Reduction :

In this reaction, the oxidation state of 'Mg' changes from (0) to (+2) that means Mg lost 2 electrons and it shows oxidation and the oxidation state of 'Fe' changes from (+2) to (0) that means Fe gains 2 electrons and it shows reduction.

Therefore, the correct option is,