Final answer:
For safety briefings at incidents with potential criminal or terrorist activities, it's most important to be alert for secondary devices to ensure the safety of everyone present.
Step-by-step explanation:
The correct option for a safety briefing at incidents involving potential criminal or terrorist activities is A. Be alert for secondary devices. This point is critical because at the scene of an incident, especially one involving criminal or terrorist activities, there is always a risk of additional threats, such as secondary explosive devices intended to cause further harm to emergency responders and bystanders.
Regarding the other options: B. Moving suspicious-looking articles could trigger a device or destroy evidence, and thus should be avoided. C. Entering damp, wet, or oily areas with caution is indeed important, but it is not specific to criminal or terrorist activities—it is a general safety practice. D. Limiting the number of personnel leaving the crime scene helps preserve evidence, but may not be directly related to immediate physical safety concerns.
It is also important to consider general laboratory safety measures such as knowing the location of safety equipment, handling chemicals carefully, and wearing appropriate protective gear, although these are not directly related to the question asked.