Explanation: The best action that the organization should take when the application owner of a system that handles confidential data leaves the organization is to assign a temporary application owner to the system. An application owner is a person or role that is responsible or accountable for the management or oversight of an application, system, or resource, that handles or processes the data or information of the organization, such as confidential, sensitive, or personal data or information. An application owner can perform various duties or tasks, such as defining, implementing, or enforcing the security policies, procedures, or standards, that govern the access or use of the application, system, or resource, as well as monitoring, reviewing, or auditing the activities, events, or transactions, that occur on the application, system, or resource. An application owner can also act as a liaison or representative between the users, stakeholders, or customers, and the developers, administrators, or providers, of the application, system, or resource, by communicating, coordinating, or collaborating with them, to ensure the functionality, performance, or security of the application, system, or resource. When the application owner of a system that handles confidential data leaves the organization, the organization should assign a temporary application owner to the system, until a permanent replacement is hired. Assigning a temporary application owner to the system can help to ensure the continuity, availability, or reliability of the system, as well as the confidentiality, integrity