The ring systems having following characteristics are aromatic. (i) Planar ring containing conjugated π bonds. (ii) Complete delocalisation of the π−electrons in ring system i.e. each atom in the ring has unhybridised p-orbital, and (iii) Presence of (4n+2) π−electrons in the ring where n is an integer (n = 0, 1, 2,...........) [Huckel rule] Using this information classify the following compounds as aromatic.