I believe the correct answer true. According to the law of conservation of mass, in a chemical reaction the total starting mass of all the reactants equals the total final mass of all the products. This law states that mass cannot be created or be destroyed. So, the total mass that goes in a process should be equal to the mass that goes out the process. This is true for chemical reactions and physical processes. It is Antoine Lavoisier who described this and is a basic principle used in physics and in chemistry. Mass, unlike energy, cannot be transformed to any form so however the transformation happens the mass should be constant.
