What is the purpose of the cisco Vlan Trunking protocol？（）

• A、to provide a mechanism to dynamically assign vlan membership to switch ports
• B、to allow traffic to be carried from multiple vlans over a single link between switches
• C、to allow native vlan information to be carried over a trunk link
• D、to provide a mechanism to manually assign vlan membership to switch ports
• E、to allow for managing the additions，deletions，and changes of vlans between switchs