The correct answer is D. methane.
A hydrocarbon is an organic compound that consists only of hydrogen and carbon atoms. Methane is the simplest hydrocarbon, with the chemical formula CH4. It is a colorless, odorless gas that is the main component of natural gas. Methane is also produced by the decomposition of organic matter, such as plants and animals.
Chlorofluorocarbons (CFCs) are a group of chemicals that were once widely used in refrigerants, aerosol propellants, and solvents. CFCs are not hydrocarbons because they contain chlorine atoms.
Acetic acid is a carboxylic acid with the chemical formula CH3COOH. It is a colorless, sour-tasting liquid that is found in vinegar. Acetic acid is not a hydrocarbon because it contains oxygen atoms.
Carbon dioxide is a gas with the chemical formula CO2. It is produced when organic matter is burned. Carbon dioxide is not a hydrocarbon because it contains oxygen atoms.