Which option best defines an organic compound?

• A. Contains carbon and hydrogen only
• B. Contains carbon and at least one of hydrogen, oxygen, or nitrogen
• C. Contains carbon and at least one noble gas
• D. Contains carbon and oxygen only

Answer: (B)

Organic compounds are built around carbon and form a huge variety of structures because carbon can bond with many elements. In most cases, these molecules contain carbon and at least one other element such as hydrogen, oxygen, or nitrogen. That combination allows simple hydrocarbons like methane (carbon and hydrogen) as well as many other organics like ethanol (carbon, hydrogen, and oxygen) or amino acids (carbon, hydrogen, oxygen, and nitrogen). The option that includes carbon plus at least one of hydrogen, oxygen, or nitrogen best captures this broad pattern. Saying it must have only carbon and hydrogen is too narrow, since many organic molecules include oxygen or nitrogen. Requiring carbon with only oxygen would exclude hydrocarbons, and tying organics to noble gases isn’t appropriate, since noble gases aren’t typical parts of organic structures.