Which deployment option will meet these requirements?

Explanations:

The “All at once” deployment strategy updates all instances simultaneously, which can lead to downtime as the new version is deployed and the old version is removed. This does not meet the requirement of avoiding downtime.

The “Rolling” deployment updates instances in batches. While it reduces the risk of downtime compared to “All at once,” it can still result in brief periods of downtime if an instance fails during the update, especially in a single-instance environment where the application is unavailable during the update process.

The “Rolling with additional batch” strategy adds extra instances to ensure capacity while the update occurs, but in a single-instance environment, there is no additional instance to utilize, resulting in potential downtime during the update process.

The “Immutable” deployment strategy creates a new set of instances with the updated application version alongside the existing instances. Once the new instances are healthy, the traffic is redirected to them, ensuring zero downtime during the deployment process. This meets the requirement effectively.