Expand each expression to a standard SOP form:

$($a$)AB+\frac{A}{b}ar(BC)+$ABC

$($b$)A+BC$

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

$($d$)\frac{A}{b}ar(B)+\frac{A}{b}ar\frac{B}{b}ar(C)D+CD+\frac{B}{b}ar(C)D+$ABCD