What feature allows you to stop an EC2 instance and resume it with its previous state?

The feature that enables you to stop an EC2 instance and subsequently resume it with its previous state is EC2 Hibernate. When you hibernate an instance, the contents of the instance's memory (RAM) are saved to the Amazon Elastic Block Store (EBS), and the instance is stopped. Upon resuming, the instance returns to its previous state, with all running applications and processes restored exactly where they left off, including in-memory data.

This capability differs significantly from other options. For example, EC2 Snapshots are used to create backups of the EBS volumes, allowing you to restore data at a point in time, but they do not preserve the state of the running instance. Spot Instances and Reserved Instances pertain to instance pricing models rather than state preservation and do not give you the ability to resume instances from their previous state after being stopped.