You are in charge of migrating a legacy application from your company datacenters to GCP before the current maintenance contract expires. You do not know what p...

You are in charge of migrating a legacy application from your company datacenters to GCP before the current maintenance contract expires. You do not know what ports the application is using and no documentation is available for you to check. You want to complete the migration without putting your environment at risk.
What should you do?

A. Migrate the application into an isolated project using a "Lift & Shift" approach. Enable all internal TCP traffic using VPC Firewall rules. Use VPC Flow logs to determine what traffic should be allowed for the application to work properly. B. Migrate the application into an isolated project using a "Lift & Shift" approach in a custom network. Disable all traffic within the VPC and look at the Firewall logs to determine what traffic should be allowed for the application to work properly. C. Refactor the application into a micro-services architecture in a GKE cluster. Disable all traffic from outside the cluster using Firewall Rules. Use VPC Flow logs to determine what traffic should be allowed for the application to work properly. D. Refactor the application into a micro-services architecture hosted in Cloud Functions in an isolated project. Disable all traffic from outside your project using Firewall Rules. Use VPC Flow logs to determine what traffic should be allowed for the application to work properly.