A web portal deployed via a single CloudFormation stack in us-east-1 uses an Elastic Load Balancer and Route 53 for DNS. The portal must be resilient across Regions. Which setup meets this requirement?

The correct answer ensures regional resilience by deploying a duplicate stack in a different region (us-west-2) and configuring Route 53 with a failover routing policy. This setup uses health checks to monitor the primary Elastic Load Balancer (ELB) in us-east-1. If the primary ELB fails, Route 53 automatically directs traffic to the secondary ELB in us-west-2, providing high availability and disaster recovery. The first incorrect option suggests a single SOA record with IP addresses, which is not how Route 53 failover with ELBs works; ELBs are typically referenced via alias records, not direct IP addresses in an SOA record. The third incorrect option only adds EC2 instances to the existing ELB in us-east-1, which does not provide cross-regional resilience if the entire us-east-1 region or its ELB fails. The fourth incorrect option involves peering VPCs and treating regions as primary/secondary, but it doesn't specify how DNS failover for the web portal would be managed, nor does it explicitly mention deploying the full stack, including the ELB, in the secondary region.