Inclusion gate as universal gate
Well, I've never heard of such a gate, however Newnes Dictionary of Electronics
 By S W Amos, Roger Amos) has. 



Fine, but I also have no idea what an IF-THEN gate might be! 

Fortunately, they do. 



So, it's like a NAND gate with an inverter on input 2. You should be able to take it from there.