When calcium carbonate is strongly heated, it decomposes according to the equation CaCO₃(s) → CaO(s) + CO₂(g). Which statement most accurately classifies this transformation?
a) It is neither a physical nor a chemical change because the total mass remains constant.
b) It is a chemical change because chemical bonds within CaCO3 are broken and new bonds are formed in the products.
c) It is a physical change because the products are in different phases (solid and gas) than the reactant.
d) It is both a chemical and a physical change because a gas is produced even though no chemical bonds change.