Which of the following could be physical evidence at a fire scene?

Physical evidence at a fire scene encompasses a variety of elements that can help in the investigation of the cause and origin of the fire. The correct choice indicates that all provided options can indeed represent physical evidence.

The type of weapon used, while primarily associated with criminal acts like arson when it involves a deliberate ignition, becomes relevant when assessing the means through which the fire was started, particularly if it involves any tools or devices designed to start or enhance a fire.

The speed at which the fire spreads can provide insight into the materials involved and the environmental conditions present during the fire, but it is more a characteristic of the fire rather than direct physical evidence. However, this information is still valuable for understanding the dynamics of the fire scene.

The scent of accelerants is a direct indicator of potential foul play. These chemical substances often leave identifiable traces that can be collected and analyzed in investigations. They are considered a form of physical evidence as they can be collected from the scene and linked to the fire's origin.

Together, all these elements contribute to a comprehensive understanding of a fire scene, making it clear that the correct answer is that they all represent forms of physical evidence in the context of fire investigations.