A developer wants to deploy a new application version to a test environment on AWS Elastic Beanstalk. Which deployment policy provides the fastest deployment time?

The "All at once" deployment policy replaces all instances in your environment with the new application version simultaneously. This is the fastest deployment method because it doesn't wait for instances to pass health checks before moving to the next batch, nor does it maintain a separate set of instances like immutable deployments. However, it incurs downtime during the update. "Immutable" deployments create a new, separate set of instances with the new version and then swap them with the old ones, ensuring zero downtime but taking longer. "Rolling" deployments update instances in batches, taking longer than "All at once" but minimizing downtime. "Rolling with additional batch" is similar to rolling but adds a temporary batch of new instances to maintain full capacity during the update, also taking longer.