Logical access control programs are most effective when they are made part of the operating system. Logical access control is the process of granting or denying access to information or resources based on the identity, role, or credentials of the user or device3. Logical access control programs, such as authentication, authorization, and auditing mechanisms, can be implemented at different levels of the system, such as the application, the database, or the network. However, the most effective level is the operating system, as it provides the lowest and most comprehensive layer of access control, and can enforce the principle of least privilege and the separation of duties for all users and processes. Approval by external auditors, combination with security token technology, and maintenance by computer security officers are not factors that affect the effectiveness of logical access control programs, as they are more related to the compliance, assurance, and administration of the access control policies. References: 3: Official (ISC)2 CISSP CBK Reference, 5th Edition, Chapter 5, page 247. : CISSP All-in-One Exam Guide, Eighth Edition, Chapter 6, page 353.