Basic Concept: VSYS capacity controls include maximum counts for certain policy and object resources. They prevent one VSYS from consuming too much configuration capacity.
Why D is Correct: A maximum number of NAT rules is a valid configurable resource limit from the listed options.
Why A is Wrong: Dedicated data plane memory 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: Maximum number of admin accounts 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 C is Wrong: Maximum number of log entries 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.