After installing some RPM packages, a systems administrator discovers the last package that was installed...

The command that can be used to remove an RPM package that was installed by mistake is dnf remove packagename. This command will use the DNF package manager to uninstall an RPM package and its dependencies from a Linux system that uses RPM-based distributions, such as Red Hat Enterprise Linux or CentOS. The DNF package manager handles dependency resolution and metadata searching for RPM packages.

The other options are not correct commands for removing an RPM package from a Linux system. The apt-get remove packagename and apt remove packagename commands are used to remove Debian packages from a Linux system that uses Debian-based distributions, such as Ubuntu or Debian. They are not compatible with RPM packages. The rpm -i packagename command is used to install an RPM package, not to remove it. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 9: Managing Software Packages; How to install/remove/query/update RPM packages in Linux (Cheat Sheet …