Determine if the cation below is aromatic, antiaromatic, or nonaromatic. If it is aromatic, determine its n in Hückel's rule. If not, explain how it breaks the aromaticity rule.

The cation is aromatic. Its n is 2.

The cation is aromatic. Its n is 4.

The cation is antiaromatic. It breaks the aromaticity rule because it does not have a (4n + 2) number of π electrons.

The cation is nonaromatic. It breaks the aromaticity rule because it is not planar.