Which of the following gases is the least common in the air A. nitrogen B.oxygen C. neon D.hydrogen?

Science. Nearly all of the Earth's atmosphere is made up of only five gases: nitrogen, oxygen, water vapor, argon, and carbon dioxide. Several other compounds also are present. ... Below is the composition of air in percent by volume, at sea level at 15 C and 101325 Pa.Aug 16, 2017
What Is the Chemical Composition of Air? - ThoughtCo
www.thoughtco.com/chemical-composition-of-air-604288
~ google.com

If you go to the link you find that hydrogen is actually much rarer than neon.