A student noticed a white coating on the magnesium metal before she started lab. She did not clean the surface of the metal. Instead she proceeded with the lab using this piece of magnesium metal. The error caused by not cleaning the magnesium metal would result in A) the mass of the magnesium recorded being erroneously high and the mass of the oxygen calculated being too low. B) the mass of the magnesium recorded being erroneously low and the mass of the oxygen calculated being too low. C) the mass of the magnesium recorded being erroneously high and the mass of the oxygen calculated being too high. D) no error in the final calculated empirical formula.