What command would you use to list installed packages on a Debian-based system?

The command to list installed packages on a Debian-based system is indeed "dpkg -l." This command utilizes the dpkg (Debian Package) tool, which is the low-level package manager for Debian and its derivatives. When executed, "dpkg -l" outputs a list of all installed packages on the system, including key details such as the package name, version number, and a brief description, which helps users understand what is currently installed.

The other options refer to package management systems that do not apply to Debian-based distributions. For instance, "apt list" is a command for listing packages from the APT package management system but may not provide as comprehensive a list as "dpkg -l." The commands "rpm -qa" and "yum list installed" pertain to Red Hat-based systems and are used to manage RPM packages. They are not suitable for use on Debian-based systems, making "dpkg -l" the correct and appropriate choice for this context.