Q$2)$ Design a $4-$input $($A$,$ B$,$ C$,$ and D$)$ digital combinational circuit that will give at its output $($W$,$ X$,$ Y$,$ and Z $)$ a binary number equal to the product of the binary numbers formed by the inputs $AB$ and $CD.$

That mean, the output is equal to $(AB**CD).$

$(15$ mark$)$