The correct answer is A. employee identification card.
In PSP-related physical security, access control is one of the core physical security countermeasures. The ASIS Certification Handbook places electronic security systems, including access control, and visitor/vendor management policies within the PSP Body of Knowledge under physical security system application, design, and integration.
An employee identification card or badge is considered a basic and long-established access control tool because it helps security personnel verify that a person belongs to the organization. It may include the employee's name, photograph, department, ID number, color coding, expiration date, or access authorization level. A security management reference also uses this exact concept, describing the employee identification card or badge as a basic and time-honored access control tool.
The other options are less accurate:
Personal recognition is a method of recognition, not a physical access control tool.
Visitor pass is mainly for temporary/non-employee access, not the basic employee access control tool.
Proximity card is an electronic access credential, but it is a more modern technology-based tool, not the classic "time-honored" one.
Therefore, the best answer is A. employee identification card.