Which yum command, when given the proper argument, displays all packages installed by yum on the system?

• A. yum list installed httpd
• B. yum list
• C. yum list all
• D. yum grouplist

Answer: (B)

The operation here is querying what yum has installed on the system. Running the list command without extra qualifiers shows a section for Installed Packages. That section contains every package that was installed through yum, so it provides a complete view of what is currently installed by yum. The other options either filter to a specific package, show all packages known to yum including those not installed, or display group information, none of which directly present the full set of installed packages. Therefore, the simplest and best way among the given choices to see all packages installed by yum is the plain list command.