What kind of fire extinguisher is designed for areas with combustible dust?

The correct answer is that a Class D fire extinguisher is specifically designed for use in areas with combustible dust. Class D extinguishers are intended for fires involving combustible metals and similar substances that can react violently with water. However, when it comes to combustible dust, it's crucial to recognize that certain classes of extinguishers will have limitations based on the specific type of dust involved.

Understanding the other options provides clarity about why they wouldn't be suitable for this scenario. For instance, Class I, II, and III extinguishers primarily address ordinary combustibles (like wood and paper), flammable liquids, and gases, respectively, but they do not specifically cater to the hazards associated with combustible dust. Therefore, for environments where combustible dust is a concern, a Class D extinguisher is essential because it effectively handles those specific fire risks, ensuring safety and compliance with fire protection regulations.