You are deploying an application that runs on Compute Engine instances. You need to determine how to expose your application to a new customer. You must ensure that your application meets the following requirements:
• Maps multiple existing reserved external IP addresses to the instance
• Processes IP Encapsulating Security Payload (ESP) traffic
What should you do?
To meet the requirement of mapping multiple existing reserved external IP addresses to the instance and processing IP Encapsulating Security Payload (ESP) traffic, you should configure a target instance and create a protocol forwarding rule for each external IP address to be mapped to the instance. This setup allows for direct forwarding of specific protocols to the appropriate virtual machine instance, which is necessary for handling ESP traffic.
Configure a target pool, and create protocol forwarding rules for each external IP address.
Protocol forwarding uses a regional forwarding rule to deliver packets of a specific protocol to a single virtual machine (VM) instance. The forwarding rule can have an internal or an external IP address. Protocol forwarding delivers packets while preserving the destination IP address of the forwarding rule. The forwarding rule references an object called a target instance, which, in turn, references a single VM instance https://cloud.google.com/load-balancing/docs/protocol-forwarding#target-instances
C. Option A is not possible.
Configure a target pool, and create protocol forwarding rules for each external IP address.
Sorry, it's C. A is not possible.
Port forwarding enabled on target instance object , not on target pool