A new packages repository named repo10 has been installed on mirror site. A Linux administrator wants to use this new repository for local package installations. In which of the following locations…

On Red Hat-based Linux systems, YUM (and DNF) repository configuration files are stored in the `/etc/yum.repos.d/` directory. Each individual repository configuration is usually defined in a separate file within this directory, conventionally ending with a `.repo` extension.

`/etc/yum_repo.d/` is not the standard directory for yum repository configurations; the correct directory uses periods, not underscores. C: While the directory is close (`yum.reps.d` is likely a typo for `yum.repos.d`), a repository configuration file conventionally uses the `.repo` extension, which is missing here. D: `/etc/yum.conf` is the main global configuration file for yum, not the location for individual repository definitions.