Which of the following is the best example of law of conservation o...

Which of the following is the best example of law of conservation of mass?

A. \(12\mathrm{g}\) of carbon combines with \(32\mathrm{g}\) of oxygen to form \(44\mathrm{g}\) of \(\mathrm{CO_2}\)

B. When \(12\mathrm{g}\) of carbon is heated in a vacuum there is no change in mass

C. A sample of air increases in volume when heated at constant pressure but its mass remains unaltered

D. The weight of a piece of platinum is the same before and after heating in air