Cisco IOS (originally Internetwork Operating System) is the software used on the vast majority of
Cisco Systems routers and all current Cisco network switches. Which two of the following devices
could you configure as a source for the IOS image in the boot system command? (Choose two.)

A.
RAM

B.
NVRAM

C.
flash memory

D.
HTTP server

E.
TFTP server

F.
Telnet server