Select ONE language $($i$.$e$.$ a set of strings$)$ from the list of items given that describes each of the following

regular expressions

Hint: Every one of these questions has an answer in the list of choices. Sometimes the answer is not totally

simplified so you might have to think about them for a little bit.

Item $1$: $\{a\}$

Item $2$: $\{ab\}$

Item $3$: $\{a,b\}$

Item $4$: $\{$aa$,$ bb$\}$

Item $5$: $\{$ab$,$ ba$\}$

Item $6$: $\{$abba$\}$

Item $7$: $\{a^n{b}^n|ninN\}$

Item $8$: $\{a^n{b}^m|n,$minN$\}$

Item $9$: $\{a^{2n}{b}^m|n,$minN$\}$

Item $10$: $\{a^n{b}^{2m}|n,$minN$\}$

Item $11$: $\{a^{n}b|ninN\}$

Item $12$: $\{a{b}^n|ninN\}$

Item $13$: $\{(ab{)}^n|ninN\}$

Item $14$: $|),(minN$ and $\{$:$n>0\}$

Item $15$: $|),(minN$ and $n>0$ and $\{$:$m>0\}$

Item $16$: $\{a^n{b}^m|n,$minN$\}\{b^m{a}^n|m,$ninN$\}$

Item $17$: $\{a^n{b}^n|ninN\}\{b^m{a}^m|minN\}$

Item $18$: $\{$a$,$ b$,$ aa$,$ ab$,$ bb$,$ ba$,$ aaa, aab, aba,

abb, baa, bab, bba, $bbb,...$

Item $19$: $\{^,$ a$,$ b$,$ aa$,$ ab$,$ bb$,$ ba$,$ aaa, aab, aba,

abb, baa, bab, bba, bbb$,...\}$