What can an Organizational Unit (OU) contain?

An Organizational Unit (OU) is a container within a directory service such as Active Directory, and it is designed to help organize and manage a network's user accounts, computers, and other resources. The correct answer indicates that an OU can contain users, groups, computers, and even other OUs. This flexibility allows administrators to create a hierarchical structure that mirrors the organization's needs, facilitating easier management of policies, permissions, and delegation of administrative tasks.

This capability of an OU to hold various objects is significant because it aids in implementing group policies across different groups or departments, applying specific configurations, and managing permissions based on organizational roles. By using OUs effectively, administrators can streamline workflow and enhance security with targeted settings.

The other options presented do not capture the complete functionality of an OU. For instance, mentioning only users and computers or only files and applications excludes key elements such as groups and the ability to nest OUs, which play crucial roles in an efficient directory structure. Similarly, stating that an OU can only contain security policies does not reflect the actual role of OUs in broader account management practices.