Which three VLAN Tagging modes are available in vSphere 6.x? (Choose three.)

External Switch Tagging (EST) is a valid vSphere VLAN mode where all VLAN tagging is performed by the physical switch and the virtual switch port is set to VLAN 0.

Private VLAN Tagging is not one of the three standard VLAN tagging modes - Private VLANs (PVLANs) are a port-isolation feature configured separately on distributed switches, not a tagging mode.

Virtual Switch Tagging (VST) is a valid mode where the vSphere Standard or Distributed Switch tags frames with the VLAN ID before they leave the host.

VXLAN Tagging is not a VLAN tagging mode in vSphere - VXLAN is a network overlay encapsulation protocol used by NSX for logical networking, distinct from the three VLAN tagging modes.

Virtual Guest Tagging (VGT) is a valid mode where the guest OS itself handles 802.1Q VLAN tagging, allowing VMs to belong to multiple VLANs simultaneously.