Identify each of the structures shown below as nonaromatic, antiaromatic, or aromatic. Provide a brief explanation for your answer.

Three chemical structures with explanations of their aromaticity status: antiaromatic and nonaromatic.

Three chemical structures with explanations indicating antiaromatic and aromatic classifications.

Three chemical structures labeled (i), (ii), (iii) with nonaromatic classifications.

Three chemical structures with explanations of their aromaticity status: antiaromatic and aromatic.