Which compound amongst the following is not an aromatic compound?

Step-by-step solution

German chemist and physicist Erich Hückel proposed a theory to help determine if a planar ring molecule would have aromatic properties. His rule states that if a cyclic, planar molecule has 4n+2 π electrons, it is considered aromatic . This rule would come to be known as Hückel's Rule In the above molecule,There is an sp 3 hybridized carbon in the ring.Hence, it is not involved in conjugation. As delocalization of π electrons is not there throughout the ring.It is not an aromatic species. It does not follow Huckel'