Basic Concept: Traffic between zones in different virtual systems requires a special zone type because no physical interface is crossed. PAN-OS uses external zones for this purpose.
Why C is Correct: External is correct because it represents the logical handoff between VSYS instances while traffic remains inside the firewall.
Why A is Wrong: Isolated mentions a VSYS, zone, or routing concept, but it does not satisfy the specific external-zone, visibility, or resource-control requirement for this virtual system design.
Why B is Wrong: Transient mentions a VSYS, zone, or routing concept, but it does not satisfy the specific external-zone, visibility, or resource-control requirement for this virtual system design.
Why D is Wrong: Internal mentions a VSYS, zone, or routing concept, but it does not satisfy the specific external-zone, visibility, or resource-control requirement for this virtual system design.
