<u>Answer:</u> The correct answer is from the substance being oxidized to the substance being reduced.
<u>Explanation:</u>
Redox reaction is defined as the reaction in which oxidation and reduction reaction occur simultaneously.
Oxidation reaction is defined as the reaction where an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.
Reducing agents are defined as the agents which reduces the other substance and itself gets oxidized. These agents undergoes reduction reactions.
Reduction reaction is defined as the chemical reaction where an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.
Oxidizing agents are defined as the agents which oxidize other substance and itself gets reduced. These agents undergoes reduction reactions.
Electrons are transferred from one atom to another in this type of reaction from the substance which is getting oxidized to the substance which is getting reduced.
It can also be said that, electrons are transferred from reducing agent to the oxidizing agent.
Hence, the correct answer is from the substance being oxidized to the substance being reduced.