The correct answer is: B. Helium
Helium is the lightest gas in the universe, and it is also non-inflammable. It is a colorless, odorless, and tasteless gas that is used in a variety of applications, including balloons, blimps, and cryogenics.
Hydrogen is the second lightest gas in the universe, and it is flammable. It is a colorless, odorless, and tasteless gas that is used in a variety of applications, including fuel cells, rockets, and airships.
Oxygen is the third lightest gas in the universe, and it is flammable. It is
a colorless, odorless, and tasteless gas that is essential for life on Earth.Nitrogen is the fourth lightest gas in the universe, and it is non-flammable. It is a colorless, odorless, and tasteless gas that is used in a variety of applications, including fertilizers, explosives, and refrigerants.