What action should an administrator take if a GPG key is not found when installing a package?

When a GPG key is not found during the installation of a package, importing the necessary GPG key is the appropriate action to take. GPG keys are utilized to verify the authenticity and integrity of software packages, ensuring that they have not been tampered with and that they originate from a trusted source.

By importing the required GPG key, the administrator enables the system to validate the package signatures successfully. This process helps maintain security by preventing the installation of potentially malicious software. Importing the key ensures that the package management system can authenticate the packages against those stored in the repository, establishing a trusted relationship between the system and the software being installed.

The other options do not effectively address the issue at hand. Reinstalling the operating system is an extreme measure that is unnecessary and would disrupt the overall system. Disabling GPG key verification compromises the security model, exposing the system to risks, as it allows any package to be installed without verification. Changing the repository settings may help if pointing to a different source, but it does not solve the problem at the root cause, which is the absence of the GPG key required for verification. Therefore, importing the necessary GPG key is the most effective and security-conscious approach to resolving this issue.