Simplify the following expression with K$-$Map:

$x\frac{?}{b}=ar\frac{A}{b}ar\frac{B}{b}ar(C)D\frac{+}{b}ar(A)BCD\frac{+}{b}ar\frac{A}{b}ar(B)CD\frac{+}{b}ar(A)\frac{B}{b}ar(C)D$