$3\mathrm{.}7$ Simplify the following Boolean expressions, using four$-$variable K$-$maps:

$($b$)A{D}^{\text{'}}+B^{\text{'}}{C}^{\text{'}}D+BC{D}^{\text{'}}+B{C}^{\text{'}}D$

$($c$){?}^{**}A{B}^{\text{'}}C+B^{\text{'}}{C}^{\text{'}}{D}^{\text{'}}+BCD+AC{D}^{\text{'}}+A^{\text{'}}{B}^{\text{'}}C+A^{\text{'}}B{C}^{\text{'}}D$