Which command enables NPIV on Cisco Nexus 5000 Series Switches and Cisco MDS switches?

A.
switch(config)# npiv enable

B.
switch(config)# npivon

C.
switch(config)# feature npiv

D.
switch(config)# npiv proxy

E.
switch(config)# np proxy-enable

Explanation:
This command enables NPIV for all VSANs on the switch.

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/nxos/san_switching/configuration/guide/b_Cisco_Nexus_7000_NXOS_SAN_Switching_Configuration_Guide/Cisco_Nexus_7000_NXOS_SAN_Switching_Configuration_Guide_chapter2.html