Give DFAs for the languages below: $($a$)$ L $=\{$ab$4$wb$2|$ w in $\{$a$,$b$\}*\}($b$)$ L $=\{$abnam $|$ n $>=3,$ m $>=2\}($c$)$ L $=\{$w$1$abbw$2|$ w$1$ in $\{$a$,$b$\},$ w$2$ in $\{$a$,$b$\}\}($d$)$ L $=\{$ban $|$ n $>=1,$ n $!=4\}$