SELinux is a free open source software project that was developed by the U$.$S$.$ National Security Agency. While it can theoretically be installed on any Linux distribution, Red Hat$-$type distributions are the only ones that come with it already set up and enabled. It uses code in Linux kernel modules, along with extended filesystem attributes, to help ensure that only authorized users and processes can access either sensitive files or system resources. There are three ways in which SELinux can be used $($Select all that apply$)$: