$(14)$ Find the grammers for sigma $=\{$a$,$b$\}$ that generate teh sets of

$($A$)$ all strings with exactly two a$$s

$($b$)$ all strings with at least two a$$s

$($c$)$ all strings with no more than three a$$s

$($d$)$ all strings with no more than three a$$s

$($e$)$ all strings taht start with a and end with b

$($f$)$ all strings with an even number of b$$s