$8$Simplify the following Boolean expressions, using four$-$variable maps:

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

$($b$){?}^{**}{x}^{\text{'}}z+w^{\text{'}}x{y}^{\text{'}}+w(x^{\text{'}}y+x{y}^{\text{'}})$

$($c$)A^{\text{'}}{B}^{\text{'}}{C}^{\text{'}}{D}^{\text{'}}+A^{\text{'}}C{D}^{\text{'}}+A{B}^{\text{'}}{D}^{\text{'}}+$ABCD$+A^{\text{'}}BD$

$($d$)A^{\text{'}}{B}^{\text{'}}{C}^{\text{'}}{D}^{\text{'}}+A{B}^{\text{'}}C+B^{\text{'}}C{D}^{\text{'}}+ABC{D}^{\text{'}}+B{C}^{\text{'}}D$