Major constituent of natural gas is

The correct answer is Option (3) → Methane

Natural gas is mostly methane (\(\ce{CH4}\)), the simplest hydrocarbon, which usually makes up 80 to 90 per cent of it or more. The rest is small amounts of heavier hydrocarbons such as ethane, propane and butane. Compressed, natural gas is sold as CNG for vehicles; propane and butane, by contrast, are the main gases of LPG, the cooking gas sold in cylinders.