Refer to the exhibit. Easy VPN operates in two modes. The exhibit represents network extension mode. Choose the best reason for using this mode.（）

• A、Teleworker devices must be accessed from the central site (server, printers).
• B、IP addressing is simplified. 
• C、The Teleworker LAN is a transit networking for routing.
• D、The Teleworker router is an MPLS PE node.