Which command adds the Fedora EPEL repository for yum?

• A. vim /etc/yum.repos.d/fedora-epel.repo
• B. gpgcheck=0
• C. baseurl=http://dl.fedoraproject.org/pub/epel/7/x86_64/
• D. yum-config-manager --add-repo=http://dl.fedoraproject.org/pub/epel/7/x86_64/

Answer: (D)

To register a new repository with yum, you need a repository definition so yum knows where to fetch packages. The direct way shown is to use a command from yum-utils that adds the repository by URL. This creates the appropriate .repo entry under /etc/yum.repos.d (including fields like baseurl and gpgkey) so yum can query that source for metadata and packages. Manually editing a file with an editor can work but is more error-prone and not as straightforward. A single setting like gpgcheck=0 or a line like baseurl=... are parts of a repo definition, not the action of adding the repo itself.