Answer the following question: $(i)$ Give the isomers of the aromatic hydrocarbon having the molecular formula $C_8H_{10}$.

(N/A) The aromatic hydrocarbon with the molecular formula $C_8H_{10}$ has four isomers:
$1$. $o$-xylene ($1$,$2$-dimethylbenzene)
$2$. $m$-xylene ($1$,$3$-dimethylbenzene)
$3$. $p$-xylene ($1$,$4$-dimethylbenzene)
$4$. Ethylbenzene