The correct answer is A. Hydrogen.
Noble gases are elements in group 18 of the periodic table. They are all gases at standard temperature and pressure and have very low chemical reactivity. Hydrogen is not a noble gas because it is a highly reactive element. It is the lightest element in the universe and is the most abundant element in the universe by mass. Hydrogen
is a colorless, odorless, and tasteless gas. It is flammable and can be explosive when mixed with oxygen.Helium is a noble gas that is colorless, odorless, and tasteless. It is the second lightest element in the universe and is the second most abundant element in the sun. Helium is used in balloons, blimps, and other inflatable objects. It is also used in cryogenics and in the production
of semiconductors.Neon is a noble gas that is colorless, odorless, and tasteless. It is the third lightest element in the universe and is the ninth most abundant element in the sun. Neon is used in signs, lasers, and other applications where a bright light is needed.
Argon is a noble gas that is colorless, odorless, and tasteless. It is the fourth lightest element in the universe and is the eighteenth most abundant element in the sun. Argon is used in light bulbs, lasers, and other applications where a non-reactive gas is needed.