You are the network administrator at Company and switch R1 is configured as shown below：  Interface gigethernet 0/1  Switchport mode trunk   Switchport trunk encapsulation dot1q  Switchport trunk native vlan 5   If untagged frames are arriving on interface gigethernet 0/1 of R1，  which of the following statement  are correct？（）

• A、 Untagged frames are automatically assumed to be in VLAN 5.
• B、 Untagged frames are defaulted to VLAN 1 traffic.
• C、 Untagged frames are dropped because all packets are tagged when dot1q trunked.
• D、 Untagged frames are determined on the other switch
• E、 Untagged frames are not supported on 802.1Q trunks.