Which of the following commands have to be used in order to update FreeBSD?

To update FreeBSD, the freebsd-update fetch command is used to download available binary updates, and the freebsd-update install command is used to apply the downloaded updates to the system. These commands are part of the freebsd-update utility, which supports binary security and errata updates to the FreeBSD base system without the need for manual compilation and installation2.

References:

FreeBSD Handbook - freebsd-update