When solid magnesium burns, it reacts with oxygen in the air to form a powder called magnesium oxide. A chemist performed this reaction in a lab and found that the mass of the magnesium oxide was greater than the mass of the magnesium. What is the reason behind this increase in mass? A. The increase in the mass of the magnesium oxide was due to magnesium atoms in the air. B. The increase in the mass of the magnesium oxide was due to oxygen atoms in the air. C. The increase in the mass of the magnesium oxide happened because magnesium is heavier than oxygen. D. The increase in the mass of the magnesium oxide happened because oxygen is heavier than magnesium.