Step 1: Recall the test
In the carbylamine test, a primary amine is heated with chloroform and alcoholic KOH to give a foul-smelling isocyanide.
Step 2: Conclude
It needs two N-H bonds to lose, so secondary and tertiary amines do not respond. Option (C).
Final Answer:
Primary amines respond, option (C).
\[ \boxed{\text{(C)}} \]