When a new trunk link is configured on an IOS based switch, which VLANs are allowed over the link?（）
- A By default, all defined VLANs are allowed on the trunk.
- B Each single VLAN, or VLAN range, must be specified with the switchport mode command.
- C Each single VLAN, or VLAN range, must be specified with the vtp domain command.
- D Each single VLAN, or VLAN range, must be specified with the vlan database command.