What is a common characteristic of cases that the Office of the Fire Marshall investigates?

The correct answer highlights that cases investigated by the Office of the Fire Marshal often involve significant loss or fatalities. This reflects the agency's primary responsibility, which is to ensure public safety by investigating fires that result in serious consequences. When a fire leads to property damage or, more importantly, injuries or deaths, it necessitates a thorough investigation to determine its cause, protect the public, and potentially hold those responsible accountable.

The nature of these serious incidents requires the expertise of the Fire Marshal's office to analyze the circumstances, establish patterns, and develop recommendations that help to prevent future occurrences. This also underscores the importance of addressing issues related to fire safety, regulations, and community awareness.

In contrast, other options suggest scenarios that don’t capture the breadth and severity of the cases typically handled by the Office of the Fire Marshal. For example, minor incidents would not ordinarily warrant the office's involvement, and public demonstrations, while they may sometimes involve fire hazards, are not a focus of the Fire Marshal's investigations. Exclusively arson cases imply a narrow scope that does not account for the variety of serious incidents the office might investigate.