$2.$ Let $\backslash$Sigma $=\{$a$,$ b$\}.$

$($i$)$ Consider the language S$$ where S $=\{$aa$,$ ab$,$ ba$,$ bb$\}.$ Give another description of this language.

$1.$ Strings of any length containing only $"$a$"$ and $"$b$".$

$2.$ The empty string $(\backslash$Lambda $)$ and all even$-$length words consisting of $"$a$"$s and $"$b$"$s$.$

$3.$ Words composed of alternating $"$a$"$s and $"$b$"$s