Which of the following best explains the Law of Conservation of Mass?

Group of answer choices:

A. In a chemical reaction the mass of the products is less than the reactants mass.

B. In a chemical reaction the mass of the products cannot be determined from the mass of the reactants.

C. In a chemical reaction mass of products always equals the mass of reactants.

D. In a chemical reaction the mass of the products is greater than the mass of reactants