Answer: The correct answer is all of these.
Explanation:
Organic compounds are defined as the chemical compounds where one or more carbon atoms are covalently bonded to other atoms of hydrogen, oxygen or nitrogen.
They occur naturally in nature and the main sources of these organic compounds are petroleum, coal and natural gases.
Petroleum are the naturally occurring substances which contain organic compounds in the form of gases, liquid or semi-solid. Thus, they are a major source of organic compound.
Coal is also a form of fossil fuel which are the major source of organic compound.
Natural gas contains hydrocarbons and also is the major source of organic compounds.
Thus, the correct answer is all of these.
