$4.$ Construct DFAs for the languages shown below in parts a$,$ b$,$ and c$.$

In all parts, $=\{,\}.$

a$.\{$w$|$ w has at least three a$$s and at least two b$$s$\}$

b$.\{$w$|$ w has has exactly two a$\text{'}$s and at least two b$$s$\}$