$($a$)$ Describe in English the language defined by the regular expression a$*(b{a}^{**}b{a}^{**}{)}^{**}.$ Your description should be a high$-$level characterization$-$one that would still make sense if we were using a different regular expression for the same language.

$($b$)$ Write an unambiguous context$-$free grammar that generates the same language.

$($c$)$ Using your grammar from part $($b$),$ give a canonical $($right$-$most$)$ derivation of the string $b,a,a,b,a,a,b.$