Which step can be used to back up the host before the upgrade is performed?

An administrator is performing an upgrade on an ESXi host.
Which step can be used to back up the host before the upgrade is performed?

A.
Using the vSphere Client connected to vCenter, right-click the host and choose Host Backup.

B.
Log into a vMA appliance and run vicfg-cfgbackup to save the ESXi host configuration.

C.
Using the vSphere Client connected directly to the host, right-click the host and choose Host
Backup.

D.
Use PowerCLI to run the host-backup cmdlet to save the ESXi host configuration.

Explanation:
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-esxivcenter-server-50-command-line-interface-solutions-and-examples-guide.pdf(page 22)