Which of the following is a package management utility for PCs that are running the Linux operating system?

`chmod` is a command used to change file permissions, not a package manager.

`yum` (Yellowdog Updater, Modified) is a widely used command-line package-management utility for Linux distributions that use RPM Package Manager, such as CentOS, Fedora, and Red Hat Enterprise Linux. It allows users to install, update, remove, and manage software packages and their dependencies.

`man` is a command used to display manual pages for other commands, not a package manager.

`grep` is a command-line utility used for searching plain-text data sets for lines that match a regular expression, not a package manager.