A primary amine has one alkyl group (or hydrogen) attached to the nitrogen, whereas secondary and tertiary amines have two and three alkyl groups, respectively.
Step 1: Understand the structure of the compound.
The given compound is CH$_3$-C-NH$_2$, where an amine group (NH$_2$) is attached to a carbonyl group (C). This is a simple primary amine, as there is only one alkyl group (CH$_3$) attached to the nitrogen atom.
Step 2: Analyze the options.
- Primary amine (Option A) is correct because the amine group is attached to one carbon atom.
- Secondary amine (Option B) would have two carbon atoms attached to the nitrogen.
- Tertiary amine (Option C) would have three carbon atoms attached to the nitrogen.
- Ammonium salt (Option D) would have a positively charged nitrogen atom, which is not the case here.
Step 3: Apply to the options.
The correct answer is (A) Primary amine.
Final Answer:
\[
\boxed{\text{Primary amine}}
\]
