$\frac{I_o}{2}$

$I_{\mathrm{o}}$

$2 I_{\mathrm{o}}$

$4 I_{\mathrm{o}}$

1/2

1

2

0

$$ \begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 0 \\ \hline \hline 0 & 1 & 0 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 0 \\ \hline \end{array} $$

$$ \begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 0 \\ \hline \hline 0 & 1 & 1 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 0 \\ \hline \end{array} $$

$$ \begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 1 \\ \hline \hline 0 & 1 & 1 \\ \hline \hline 1 & 0 & 1 \\ \hline \hline 1 & 1 & 0 \\ \hline \end{array} $$

$$ \begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 1 \\ \hline \hline 0 & 1 & 0 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 0 \\ \hline \end{array} $$