what is the cause of the problem?

Refer to the exhibit.

The link between switch SW1 and switch SW2 is configured as a trunk, but the trunk failed to
establish connectivity between the switches. Based on the configurations and the error messages
received on the console of SW1, what is the cause of the problem?

A.
The two ends of the trunk have different duplex settings.

B.
The two ends of the trunk have different EtherChannel configurations.

C.
The two ends of the trunk have different native VLAN configurations.

D.
The two ends of the trunk allow different VLANs on the trunk.

Explanation:
The native VLAN, if not explicitly configured, will default to the default VLAN, (VLAN1). The Native
VLAN is configured for an 802.1Q Trunk port. 802.1Q trunks carry traffic from multiple VLANs by
tagging the traffic with VLAN identifiers (Tagged Traffic) which identifies which packets are
associated with which VLANs, and they can also carry non VLAN traffic from legacy switches or
non 802.1Q compliant switches (Untagged Traffic). The switch will place untagged traffic on the

Native VLAN by using a PVID identifier. Native VLAN traffic is not tagged by the switch. It is a best
practice to configure the Native VLAN to be different than VLAN1 and to configure it on both ends
of the trunk.