Which APT command completely removes a package along with its configuration files?

The command that completely removes a package along with its configuration files is the option that utilizes the "-purge" flag. When using the Advanced Package Tool (APT) in Debian-based systems, this option not only uninstalls the package but also cleans up any associated configuration files that may have been left behind.

This is particularly useful in scenarios where a user wants to ensure that no remnants of the package exist on the system after it has been removed, which can help in preventing conflicts or issues if the package is installed again later.

The other options represent common terminology one might encounter, but they are not correct in the context of APT commands. For example, "-remove" is similar to "purge" but only removes the package itself without touching the configuration files. Meanwhile, "-delete" and "-uninstall" do not exist as valid flags within the APT system for managing packages. Thus, the preceding understanding of package management within APT reinforces why "-purge" is the appropriate choice in this context.