Which three statements about the DHCP snooping feature on Cisco Nexus switches are true？ （）

• A、 DHCP snooping commands are not available until the feature is enabled with the feature dhcp- snooping command.
• B、 When you enable the DHCP snooping feature， the switch begins building and maintaining the DHCP snooping binding database.
• C、 The switch will not validate DHCP messages received or use the DHCP snooping binding database to validate subsequent requests from untrusted hosts until DHCP snooping is enabled globally and for each specific VLAN.
• D、 Globally disabling DHCP snooping removes all DHCP snooping configuration on the switch.
• E、 Globally disabling DHCP snooping does not remove any DHCP snooping configuration or the configuration of other features that are dependent upon the DHCP snooping feature.