Basic Concept: When routes to the same destination are learned from different routing protocols, PAN-OS compares administrative distance before metrics from the same protocol.
Why D is Correct: The lowest administrative distance wins because it represents the most preferred route source; higher values are less trusted.
Why A is Wrong: The route that was received first will be entered into the forwarding table, and all subsequent routes will be rejected. is a routing-related concept, but it is not the PAN-OS routing attribute, prerequisite, or route-selection behavior required by this question.
Why B is Wrong: It will attempt to load balance the traffic across all routes. is a routing-related concept, but it is not the PAN-OS routing attribute, prerequisite, or route-selection behavior required by this question.
Why C is Wrong: It compares the administrative distance and chooses the one with the highest value. is a routing-related concept, but it is not the PAN-OS routing attribute, prerequisite, or route-selection behavior required by this question.
