Two specific users need access to a directory owned by root where backups are located. Which of the following commands would BEST ensure the specified users can access the backup files?

`umask` sets default permissions for newly created files and directories; it does not modify permissions on existing files or grant access to specific users.

`chcon` changes the SELinux security context of files, which is a different security mechanism and does not directly grant standard file system access to users.

`chmod` changes standard file permissions (owner, group, other) and is not ideal for granting access to *two specific users* without affecting other users or creating a new group.

`setfacl` (set File Access Control Lists) allows an administrator to define more granular permissions for files and directories than traditional Unix permissions. It enables specific users or groups, beyond the file's owner and primary group, to be granted read, write, or execute access without altering the file's ownership or standard group permissions.