I think it’s c cause height is what determines gravitational potential energy
I am assuming you are talking about Neon. The rate of diffusion is directly proportional to the molar mass of the gas. Since neon has a molar mass of 20.18 grams, the gas must have a lower molar mass and must be a gas at 273 Kelvin. There are several elements that fulfill this criteria: Hydrogen, Helium, Oxygen, Nitrogen, and Fluorine.
one mole of sulfuric acid will contain 2 moles of hydrogen atoms. The molar mass of sulfuric acid is 98.0795 g/mol. This means that every mole of sulfuric acid has a mass of 98.0795 g. Since you're dealing with one mole of sulfuric acid, it follows that you will also be dealing with two moles of hydrogen.