Solution :Diazotisation [action of nitrous acid `(NaNO_(2)+HCL)`] is given by an aromatic primary AMINE (having- `NH_(2)` group directily attached to nucleus), in an inorganic acid leading to the formation of diazonium SALT. In option (b) `-NH_(2)` is not LINKED directly to the BENZENE nucleus hence will not go for diazotisation.