Write the structural formulae of all the isomers of hexane $(C_6H_{14})$.

(N/A) Hexane $(C_6H_{14})$ has five structural isomers:
$(a)$ $n$-Hexane: $CH_3-CH_2-CH_2-CH_2-CH_2-CH_3$
$(b)$ $2$-Methylpentane: $CH_3-CH(CH_3)-CH_2-CH_2-CH_3$
$(c)$ $3$-Methylpentane: $CH_3-CH_2-CH(CH_3)-CH_2-CH_3$
$(d)$ $2,2$-Dimethylbutane: $CH_3-C(CH_3)_2-CH_2-CH_3$
$(e)$ $2,3$-Dimethylbutane: $CH_3-CH(CH_3)-CH(CH_3)-CH_3$