Which statement is true about organic amines?

The statement that organic amines are derived from ammonia is true. Organic amines are compounds that contain an amine group (-NH2, -NR2, where R represents a carbon-containing group) and are formed by substituting one or more hydrogen atoms in ammonia (NH3) with organic radical groups. This makes them chemically related to ammonia while incorporating carbon, thus classifying them as organic compounds.

Regarding the other options, the claim that they are always solids at room temperature is inaccurate, as many organic amines can exist as gases or liquids depending on their molecular structure and the length of their carbon chains. It's also incorrect to say that they typically have no odor; many amines, particularly those with shorter carbon chains, have distinctly strong odors. Furthermore, the assertion that they contain only carbon and hydrogen is false; organic amines must contain nitrogen as part of their structure, which differentiates them from hydrocarbons.