What is an organic compound?

• A. A polymer of sulfur.
• B. Inorganic salts only.
• C. Carbon-based molecules.
• D. A compound without carbon.

Answer: (C)

Organic compounds are carbon-based molecules. The defining feature is that they contain carbon, most often bonded to hydrogen, forming the backbone of countless structures from simple chains to complex rings and large biomolecules. This carbon-centered chemistry arises because carbon can form four covalent bonds and build diverse, stable frameworks, enabling a vast array of shapes, functional groups, and reactions that drive biology and materials science.

Some carbon-containing substances are often treated as inorganic in traditional definitions (for example, carbon dioxide or carbonates), but the general idea taught in early chemistry is that organic compounds are those built around carbon, especially with hydrogen attached.

So the option describing carbon-based molecules best matches what an organic compound is. The other choices describe substances that either lack carbon entirely or are characteristic of inorganic chemistry, such as inorganic salts or polymers of sulfur.