DHCP snooping on Cisco Nexus 1000V Series Switches acts like a firewall between untrusted hosts and trusted DHCP servers by doing which of these？ （）

• A、 validates DHCP messages received from untrusted sources and filters out invalid response messages from DHCP servers
• B、 intercepts all ARP requests and responses on untrusted ports
• C、 builds and maintains the DHCP snooping binding database， which contains information about untrusted hosts with leased IP addresses
• D、 uses the DHCP snooping binding database to validate subsequent requests from untrusted hosts
• E、 limits IP traffic on an interface to only those sources that have an IP-MAC address binding table entry or static IP source entry