An application runs on several Amazon EC2 instances, each with multiple Amazon Elastic Block Store (Amazon EBS) data volumes attached. The EC2 instance configuration and data need nightly backups, and the application must be recoverable in a different AWS Region. Which solution meets these requirements with the MOST operational efficiency?

The most operationally efficient solution is to use AWS Backup. AWS Backup is a fully managed backup service that centralizes and automates data protection across AWS services. By creating a backup plan and adding the EC2 instances as resources, AWS Backup will automatically handle the backup of all attached EBS volumes and the EC2 instance configuration (including AMIs), ensuring comprehensive nightly backups. The service also simplifies cross-Region replication for disaster recovery, fulfilling the requirement for recoverability in a different AWS Region. Using a Lambda function to schedule EBS snapshots is less efficient because it requires custom code development and maintenance, and it would only back up the EBS volumes, not the EC2 instance configuration. Copying snapshots to a different Availability Zone does not meet the requirement for cross-Region recovery. While backing up EBS volumes directly with AWS Backup is possible, adding the EC2 instances as resources is more comprehensive as it includes the instance configuration, which is crucial for full application recovery.