What is an example of a physical security measure?

The correct answer is noted for being a practical example of a physical security measure because security cameras and access control systems are designed to protect physical premises and assets from unauthorized access and monitor activities in physical spaces. Security cameras serve as a deterrent and provide surveillance, while access control systems regulate who can enter specific areas, thereby securing facilities from potential threats.

In contrast, encryption protocols, firewalls, and intrusion detection systems are primarily associated with cybersecurity measures that protect information technology systems and networks from digital threats. These options do not directly address the physical security aspect but are essential for safeguarding data and computer systems. This distinction helps to clarify why the first choice is the best example of a physical security measure in the context of the question.