Step-by-step explanation:
Magnets have the property where opposite poles attract each other and same poles repel each other. The single magnet in this case repels the stack of magnets which means that the poles of the single magnet and stack of magnet are same.
Metals are not permanent magnets. Temporary magnetism can be induced in metal by bringing a magnet close to it. The poles of the metal surface will be such that it is attracted by the magnet.