An enterprise is designing a disaster recovery strategy for a critical application. The application uses Amazon EC2, Amazon RDS, and Amazon S3. The business requires a Recovery Time Objective (RTO) of 4 hours and a Recovery Point Objective (RPO) of 1 hour. They want to minimize costs while meeting these requirements. Which DR strategy is the MOST cost-effective?

Pilot Light: Replicate data to the DR region. Maintain a minimal version of the core infrastructure (e.g., RDS read replica). Scale up EC2 instances only during a disaster.

Backup and Restore: Take hourly snapshots of RDS and EBS. Copy them to the DR region. Restore everything from snapshots during a disaster.

Warm Standby: Maintain a scaled-down but fully functional version of the application in the DR region. Scale up during a disaster.

Multi-Site Active-Active: Run the full application stack in both regions simultaneously and route traffic using Route 53.