Answer
General representation of (a) primary amine is $R-NH_{2}$, (b) secondary amine is $R-NH-R'$and (c) a tertiary amine is $R-NR'R''$ see below picture.
R, R' and R'' are alkyl groups which may be same or different alkyl groups.
d)This is not a secondary amine. As we can see that N atom is bonded with 2 H atoms. So, this is an example of primary amine not a secondary one. (see figure d below)
Work Step by Step
Primary amine is when N atom in the particular amine molecule is bonded with 2 no. of H atoms.
Secondary amine is when the N atom is bonded with 1 H atom.
and tertiary amine is when there is no H atom bonded with the N atom.
