(N/A) compound is considered aromatic if it follows $H$ückel's rule,which states that the molecule must be cyclic,planar,fully conjugated,and contain $(4n + 2) \pi$ electrons,where $n$ is an integer $(n = 0, 1, 2, ...)$.
$1$. Benzene $(C_6H_6)$: It is a cyclic,planar molecule with a continuous ring of $p$-orbitals. It contains $3$ double bonds,resulting in $6 \pi$ electrons. Applying $H$ückel's rule: $4n + 2 = 6$,which gives $n = 1$. Since $n$ is an integer,benzene is aromatic.
$2$. Naphthalene $(C_{10}H_8)$: It consists of two fused benzene rings. It is cyclic,planar,and fully conjugated. It contains $5$ double bonds,resulting in $10 \pi$ electrons. Applying $H$ückel's rule: $4n + 2 = 10$,which gives $4n = 8$ or $n = 2$. Since $n$ is an integer,naphthalene is aromatic.