Which is a common cause of structural fires?

The correct answer is that electrical malfunctions are a common cause of structural fires. Electrical systems are a critical component of most buildings, and when they are improperly installed, maintained, or overloaded, they can generate heat and sparks that lead to fires. Faulty wiring, malfunctioning circuit breakers, and using devices beyond their rated capacity are all scenarios that can initiate a fire. These incidents happen frequently and often lead to significant property damage or even loss of life.

While other options like high winds could contribute to the spread of fires or human error in evacuations might increase risk during a fire emergency, they are not direct causes of structural fires themselves. Improper use of cooking appliances is indeed a common cause of fires as well, especially in residential settings, but electrical malfunctions tend to be more prevalent and widespread as a trigger for fire incidents across various types of buildings.