A computer is connected to the network through a NIC， which has a unique assignment that is called the Ethernet MAC address. Which layer of the OSI model does the MAC address use to communicate with the network？（）

A. PAT
B. CAT
C. NAT
D. DAT
E. FAT

A. passive optical network （PON）
B. serial
C. Fibre Channel
D. Fast Ethernet
E. ADSL2+

A. Cisco Intrusion Prevention System
B. DMZ
C. business-grade firewall
D. Cisco Small Business Pro Service
E. VPN capabilities
F. ProtectLink Gateway