What document must security guards carry while on duty?

Security guards are required to carry their security license while on duty because it serves as proof of their authorization to perform security-related tasks. This document is essential for validating their identity and professional status, ensuring that they are recognized as licensed security personnel by both the public and law enforcement. Carrying the license is a standard practice that enhances accountability and provides assurance that the individual has completed the necessary training and meets the legal requirements to work as a security guard.

The other options, although potentially useful for a security guard's daily responsibilities, do not fulfill the legal requirement of carrying proof of licensure. A flashlight may be beneficial in low-light situations, a first aid kit is useful for medical emergencies, and a notepad can help in recording observations; however, none of these are mandated documents that confirm a guard’s authorized capacity to act in their role. Thus, the possession of a security license is a crucial aspect of a security guard's duties, ensuring compliance with regulatory standards.