A. Use AWS Config to detect whether an Internet Gateway is added and use an AWS Lambda function to provide auto-remediation.
B. Within the Amazon VPC configuration, mark the VPC as private and disable Elastic IP addresses.
C. Use IPv6 addressing exclusively on the EC2 hosts, as this prevents the hosts from being accessed from the internet.
D. Move the workload to a Dedicated Host, as this provides additional network security controls and monitoring.