(b)
When the nucleophilic site is the same, nucleophilicity parallels basicity. It means more basic the nucleophile, stronger is the nucleophile.
[image:12_image310.emf]is the most nucleophilic
[image:12_image311.emf]
Furthermore the $NH_{2}$ group away from the $–C -$group is not involved in resonance. Hence, its lone pair is reading available.