Which three commands can be used to harden a switch? (Choose three.)
A. switch(config-if)# spanning-tree bpdufilter enable
B. switch(config)# ip dhcp snooping
C. switch(config)# errdisable recovery interval 900
D. switch(config-if)# spanning-tree guard root
E. switch(config-if)# spanning-tree bpduguard disable
F. switch(config-if)# no cdp enable
