The correct answer is D. Nitrogen.
Nitrogen is an inert gas, which means that it does not react with other substances. This makes it ideal for use in packaging foods and chips, as it prevents them from being oxidized. Oxidation is a chemical reaction that occurs when oxygen combines with other substances, and it can cause foods to spoil. By packaging foods in nitrogen, manufacturers can extend their shelf life and prevent them from becoming rancid.
Hydrogen is a flammable gas, and it would be dangerous to use it in packaging foods. Oxygen is necessary for life, but it can also cause foods to spoil. Chlorine is a toxic gas, and it would be dangerous to use it in packaging foods.
Therefore, the only gas that is safe and effective for use in packaging foods is nitrogen.