iv$)$ Use the Karnaugh Map method to simplify the following expression:

$F=\frac{A}{b}ar\frac{B}{b}ar(C)+A\frac{B}{b}ar\frac{C}{b}ar(D)\frac{+}{b}ar\frac{A}{b}ar\frac{B}{b}ar(C)D\frac{+}{b}ar\frac{A}{b}ar\frac{B}{b}ar\frac{C}{b}ar(D)$