Which of the following is NOT a class of fire?

The classification of fires is based on the materials that are burning and the appropriate extinguishing agents to use. Classes A, B, and C are recognized categories:

• Class A fires involve ordinary combustible materials such as wood, paper, and cloth.
• Class B fires consist of flammable liquids and gases, including gasoline and oil.
• Class C fires are electrical fires that occur in energized electrical equipment.

While there is indeed a Class D fire, which is associated with combustible metals like magnesium and sodium, it is not included in the context of the question regarding which is NOT a class of fire. The other three classes (A, B, and C) are well-established and recognized in firefighting literature and practices. As a result, identifying Class D as the option that does not belong aligns with the knowledge of fire classifications, as it suggests a misunderstanding of fire types rather than confirming that all provided options are equally related.