Which one of the following compound gives foul smelling compound when heated with chloroform and alcoholic caustic potash ?

Carbyl amine test is a test used to identify primary amines.

${\mathrm{RNH}}_2\underset{\mathrm{alc}.\mathrm{KOH},∆}{\overset{{\mathrm{CHCl}}_3}{\to }} \mathrm{R}-\mathrm{NC}$.

(1) is a secondary amine whereas (2) is a tertiary amine.

 (3)…. Amides cannot give positive carbyl amine test.

Only (4) is a primary amine (CH₃-CH₂-CH₂-NH₂) which has a   -NH₂ group.