Which of the following choices is NOT a Class B fire?

Class B fires are defined as fires that involve flammable liquids or gases. These types of fires are commonly associated with materials such as gasoline, oil, and various solvents. The substances that fall into this category ignite easily and can spread quickly, making it essential to use the appropriate fire suppression methods for these situations.

When it comes to wood, it is classified as a solid combustible material, which places it squarely in the realm of Class A fires. Class A fires typically involve ordinary combustibles like paper, wood, cloth, and many plastics. Therefore, wood does not fit the definition of a Class B fire, making the choice concerning wood the correct answer in identifying what is NOT a Class B fire. Understanding the classifications of fires is crucial for effective fire safety training and the use of the right extinguishers based on the fire type.