Which of the following is an example of a physical security control?

A biometric access system is indeed an example of a physical security control because it is a technology that grants access to a physical location based on the verification of physical characteristics unique to an individual, such as fingerprints, retinal scans, or facial recognition. This type of control is specifically designed to protect physical spaces like buildings or secure areas by ensuring that only authorized personnel can enter.

On the other hand, encryption software, firewalls, and intrusion detection systems serve as logical or technical security controls. They are primarily focused on protecting data, networks, and systems from unauthorized access and cyber threats, rather than physical access to specific locations. While all these controls are essential components of a comprehensive security strategy, the biometric access system distinctly classifies as a physical control focused on securing actual physical premises.