The correct answer is A. In Google Cloud VPCs, the priority of firewall rules is crucial. Rules with a lower priority number take precedence over those with a higher number. To configure the fewest open egress ports, you should set up a high-priority rule (with a low number like 1000) that allows traffic only on the specific needed ports, while setting a low-priority rule (with a high number like 65534) that blocks all egress traffic. This ensures that the general block-all rule is overridden by the specific allow rule for the necessary ports, achieving the goal of minimizing open egress ports.