The correct option is A n - butylamine
n-butylamine (CH3CH2CH2CH2NH2) can be prepared by Gabriel phthalimide reaction. This method produces only primary amines without the traces of secondary or tertiary amines. In this method, phthalimide is treated with ethanolic KOH, it forms potassium salt of phthalimide which on heating with alkyl halide followed by alkaline hydrolysis forms corresponding primary amines.
Triethylamine, t-butylamine and neo-pentylamine cannot be prepared by Gabriel phthalimide reaction.