The requirement is to allow clients within the same VPC to resolve the IP address of the HTTP API hosted on a Compute Engine VM. Option B correctly leverages Compute Engine's internal DNS, which resolves the instance name to its internal IP address. The URL format provided in B matches the structure of internal DNS names ([INSTANCE_NAME].[ZONE].c.[PROJECT_ID].internal), ensuring clients within the VPC can resolve the IP. Options A and C involve external IP addresses via HTTP(S) load balancing, which exposes the service publicly, violating the internal-only access requirement. Option D uses an incorrect URL format for internal DNS. Thus, B is the only valid solution.