How do you activate new firmware on the Cisco UCS C-Series server?

How do you activate new firmware on the Cisco UCS C-Series server?

A.
It is activated by switching the server to the new firmware after a system reboot.

B.
It is activated by reinstalling the server operating system.

C.
It is activated when the firmware is installed on the server.

D.
It is activated by downloading the desired images from Cisco Connection Online and copying them to a network server.