Explanation: The correct approach is to create an HA VPN gateway and associate it with the encrypted VLAN attachments. The same Cloud Router used for BGP sessions with Cloud Interconnect can be used for the HA VPN. This configuration ensures encryption of the traffic passing over the Cloud Interconnect links.
: Google Cloud HA VPN over Cloud Interconnect

The correct answer is C. Configure a target instance, and create a protocol forwarding rule for each external IP address to be mapped to the instance.
This answer is based on the following facts:
A target instance is a Compute Engine instance that handles traffic from one or more forwarding rules1. You can use target instances to forward traffic to a single VM instance from one or more external IP addresses2.
A protocol forwarding rule specifies the IP protocol and port range for the traffic that you want to forward3. You can use protocol forwarding rules to forward traffic of any IP protocol, including ESP4.
The other options are not correct because:
Option A is not possible. You cannot create protocol forwarding rules for a target pool. A target pool is a group of instances that receives traffic from a network load balancer5.
Option B is not suitable. You do not need to create an external network load balancer for each external IP address. An external network load balancer distributes traffic among multiple backend instances based on the destination IP address and port. You can use a single load balancer with multiple forwarding rules to map multiple external IP addresses to the same backend service.
Option D is not feasible. You cannot add multiple external IP addresses to a single network interface of a Compute Engine instance. Each network interface can have only one external IP address that is either ephemeral or static. You can use alias IP ranges to assign multiple internal IP addresses to a single network interface, but not external IP addresses.

For GKE pods that need to egress directly to the internet for most of their communications, the most cost- efficient and straightforward approach is to deploy a GKE cluster with public cluster nodes. Public nodes have external IP addresses, allowing pods to directly reach the internet. This eliminates the need for additional services like Cloud NAT or Secure Web Proxy for outbound internet access, which would incur extra costs and management overhead.
Exact Extract:
"Public clusters have nodes with external IP addresses, allowing them to directly initiate connections to the internet. This is the simplest configuration for clusters that require direct internet egress for their workloads."
"When using public clusters, Cloud NAT is not required for outbound internet connectivity from the nodes or pods, as they can use their external IP addresses. This can reduce operational overhead and cost compared to private clusters that need NAT."Reference: Google Kubernetes Engine Documentation - Cluster network configuration, Public clusters vs Private clusters