In a redox reaction, what is the role of a 'reducing agent'?

The correct option is: "It is a substance that causes reduction and itself gets oxidized."

To understand the role of a reducing agent, we can break down the process of a redox (reduction-oxidation) reaction into its two main simultaneous components: oxidation and reduction.

First, let's look at the definitions of these processes in terms of electron transfer:
1. Oxidation is the loss of electrons by a substance.
2. Reduction is the gain of electrons by a substance.

A reducing agent (also called a reductant) is the reactant that brings about reduction in another substance. Since reduction requires the gain of electrons, the reducing agent must supply or donate these electrons to the substance being reduced.
By donating its own electrons to help the other substance undergo reduction, the reducing agent itself loses those electrons. Since losing electrons is defined as oxidation, the reducing agent undergoes oxidation during the reaction.

Therefore, a reducing agent is defined as a substance that causes reduction in another reactant while itself getting oxidized.