Which of the following is considered a basic method to ensure confidentiality?

Ensuring confidentiality involves protecting sensitive information from unauthorized access and disclosure. Physical security measures are fundamental practices that help to safeguard environments where sensitive data is stored or processed. By implementing robust physical security measures such as locked doors, security personnel, surveillance cameras, and access control systems, organizations can significantly mitigate the risk of unauthorized individuals gaining access to confidential information.

These measures create a physical barrier that is essential for protecting assets and data, especially in environments that handle sensitive or proprietary information. For instance, if a server room is not secured physically, it becomes vulnerable to tampering or unauthorized access, which would compromise the confidentiality of the data stored on those servers.

The other options, while they may play important roles in an organization's overall security posture, do not directly focus on safeguarding confidentiality in the same way. Financial auditing relates more to ensuring integrity and accuracy in financial records than to protecting sensitive information. Cloud storage solutions can provide secure avenues for data storage, but they must be complemented with physical security controls and data protection policies. Employee scheduling does not directly pertain to confidentiality, although managing personnel access can indirectly affect who can access certain information. Thus, physical security measures stand out as a direct method for ensuring confidentiality.