Name the only metal that is antibacterial.

Copper

The correct answer is option 4. Copper.

Copper is the only metal known to have intrinsic antibacterial properties. It exhibits antimicrobial activity against a wide range of bacteria, viruses, and fungi. This property has been recognized for centuries, and copper has been utilized in various applications to reduce the spread of infections. Copper surfaces can inhibit the growth and survival of microorganisms, making them useful in settings where hygiene is essential, such as hospitals, public spaces, and food processing facilities.