Explanation

Hydrogen indeed has three isotopes (protium, deuterium, tritium); oxygen is used as the oxidizer for rocket fuels; and nitrogen flushing replaces air in food packaging to prevent oxidation. Electric bulbs, however, are filled with inert gases like argon or nitrogen, not helium — helium is used in balloons, deep-sea diving mixtures and cryogenics because it is light and inert but it is not the standard bulb fill gas. The statement about helium is therefore the incorrect one. Hence option B is correct.