b$)$ Draw a network which will add three $2-$bit binary number to give a $4-$bit sum. That is add:

$S=x+Y+Z$

where. $x=x_1{x}_0,Y=y_1{y}_0,Z=z_1{z}_0$ and $S=s_3{s}_2{s}_1{s}_0$

l'se Full adders only in your circuit.