Which statement describes inorganic substances?

• A. They contain carbon
• B. They come from living things
• C. They do not contain carbon
• D. They are inorganic

Answer: (C)

Inorganic substances are typically described as compounds that do not rely on carbon–hydrogen bonds. Because organic chemistry centers on carbon-based, hydrogen-containing structures, the simplest and most common description for inorganic substances is that they do not contain carbon. This helps explain why minerals, salts, metals, and many simple acids fit into inorganic chemistry.

So the statement that they do not contain carbon best captures the usual way this category is defined in this level of environmental chemistry. While there are carbon-containing inorganic compounds in real chemistry, the standard classroom distinction emphasizes the absence of carbon in many inorganic substances, which is why this option fits the description best.