The correct answer is:
It shows that no atoms have been gained or lost during the reaction.
The Law of Conservation of Mass states that in a chemical reaction, the mass of the reactants must equal the mass of the products. This means that the number of atoms of each element in the reactants must equal the number of atoms of each element in the products, indicating that no atoms are lost or gained in the process. In the balanced chemical equation provided, the number of each type of atom is the same on both sides of the equation, demonstrating this law.