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

K$-$maps:

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

$($d$)wxy+xz+w{x}^{\text{'}}z+w^{\text{'}}x$