Question $3$: Construct NFA $($state diagram form$)$ that accepts a language L over input alphabet $\backslash$Sigma $=\{$a$,$b$\},$ such that:

$($a$)$ L$=\{$w$|$ w contains an even number of a$\text{'}$s$,$ and contains exactly two b$$s$\}$ and NFA has exactly $6$ states.

$($b$)$ L is language given using regular expression a$*.$ NFA should have one state only.

$($c$)$ L $=\{$w$|$ w contains string baba$\}$ and NFA has exactly $5$ states.

$($d$)$ L$=\{$w$|$ w doesn$$t contain b$\}$ with one state only.