To ensure Amazon EC2 instances remain available even if a natural disaster impacts a specific geographic area, which solution should be used?

Deploying EC2 instances in multiple AWS Regions provides the highest level of disaster recovery and business continuity. Each AWS Region is a distinct geographic area, isolated from other Regions, meaning a natural disaster impacting one Region will not affect instances in another. This ensures application availability even in the event of a widespread regional outage. Deploying across multiple edge locations is incorrect because edge locations are part of CloudFront's global network for content delivery, not for hosting EC2 instances for disaster recovery. Deploying in the same Availability Zone but across different AWS Regions is a contradictory statement; Availability Zones are contained within a single Region. Using Amazon CloudFront with EC2 instances as the origin improves content delivery performance and caching but does not inherently provide disaster recovery for the EC2 instances themselves in the event of a regional outage.