Step 1: Define chloroform.
Chloroform is a chemical compound with the formula \( \text{CHCl}_3 \). It is a type of halogenated hydrocarbon where three chlorine atoms are bonded to a single carbon atom, along with one hydrogen atom.
Step 2: Understand the classification of chloroform.
Since chloroform contains three chlorine atoms attached to a carbon, it is classified as a trihalogen derivative. A trihalogen derivative contains three halogen atoms attached to a carbon atom.
Step 3: Eliminate the incorrect options.
- Option (A) Primary halide: Incorrect, as chloroform is not a primary halide (it has three halogen atoms).
- Option (B) Tertiary halide: Incorrect, a tertiary halide has three alkyl groups attached to the carbon atom, which is not the case with chloroform.
- Option (C) Trihalogen derivative: Correct, chloroform is a trihalogen derivative because it contains three chlorine atoms attached to one carbon.
- Option (D) Tetrahalogen derivative: Incorrect, chloroform has three halogen atoms, not four.
Final Answer:
\[
\boxed{\text{Trihalogen derivative}}
\]