Which extinguisher is designed for combustible metals?

The correct answer is designed specifically for extinguishing fires involving combustible metals, such as magnesium, aluminum, and titanium. These types of metals burn at very high temperatures and can react violently with water or foam, making conventional extinguishing agents ineffective and sometimes dangerous to use in such situations. Class D extinguishers utilize dry powder agents that smother the fire and create a barrier between the burning metal and the environment, effectively preventing the fire from spreading and ensuring safety.

The other classifications do not address the specific hazards associated with combustible metals. Class A extinguishers are intended for ordinary combustible materials like wood and paper. Class B extinguishers are for flammable liquids and gases. Class C extinguishers are suited for electrical fires. Therefore, only Class D is appropriate for the unique challenges posed by fires involving combustible metals.