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

To list all installed packages on a Debian-based system, both the command "apt list --installed" and "dpkg -l" are valid options, making the choice of both commands the correct answer.

The command "apt list --installed" utilizes the APT (Advanced Package Tool) package management system, which provides a user-friendly interface that not only lists installed packages but also offers additional information about package versions and status. This command is particularly useful for users who prefer the high-level operations of APT.

On the other hand, "dpkg -l" interacts directly with the Debian package manager (dpkg) and displays a detailed list of all installed packages, as well as their versions and status. It is a lower-level command that works independently of APT, providing precise information on the packages managed by the system.

Using either command will yield a comprehensive view of installed packages, hence making the option that includes both commands the most complete and accurate choice.