Option A is correct because it effectively blocks all egress traffic by default with a low-priority rule and only allows traffic through specific ports with a high-priority rule, ensuring minimal open egress ports. This approach is secure and meets the requirement of controlling data egress tightly. Option B is incorrect as firewall rules cannot simultaneously manage both ingress and egress traffic. Option C is flawed because a high-priority rule blocking all egress would override any low-priority allow rules, resulting in no egress traffic being permitted. Option D does not address the need to block all egress traffic by default, leaving unnecessary ports open. For more details, refer to Google Cloud's firewall documentation.