(A) Gabriel phthalimide synthesis is used for the preparation of primary $(1^{\circ})$ aliphatic amines.
$1$. $(CH_3)_2CH-CH_2-NH_2$ is a primary aliphatic amine. It can be synthesized by this method.
$2$. $CH_3CH_2NH_2$ is a primary aliphatic amine. It can be synthesized by this method.
$3$. $C_6H_5-CH_2-NH_2$ (benzylamine) is a primary amine where the $-NH_2$ group is attached to an aliphatic carbon. It can be synthesized by this method.
$4$. $C_6H_5-NH_2$ (aniline) is an aromatic amine. Aromatic primary amines cannot be prepared by Gabriel phthalimide synthesis because aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.
Thus,there are $3$ such amines that can be synthesized by this method.