The correct answer is D. Methane.
Methane is a colorless, odorless gas that is lighter than air. It is the principal component of natural gas and is also produced by the decomposition of organic matter in swamps, landfills, and sewage treatment plants. Methane is a greenhouse gas that is more potent than carbon dioxide.
Carbon monoxide is a colorless, odorless gas that is toxic to humans. It is produced by incomplete combustion of carbon-containing fuels, such as gasoline, coal, and natural gas. Carbon monoxide can also be produced by the decomposition of organic matter in swamps and landfills.
Carbon dioxide is a colorless, odorless gas that is a major component of the
Earth’s atmosphere. It is produced by the respiration of animals and plants, as well as by the burning of fossil fuels. Carbon dioxide is a greenhouse gas that contributes to climate change.Sulphur dioxide is a colorless, odorless gas that is produced by the burning of fossil fuels that contain sulphur. Sulphur dioxide is a major air pollutant that can cause respiratory problems in humans.
In conclusion, the gas produced in marshy places due to decomposition of vegetation is methane.