You have a Recovery Services vault used for testing backups; the test backups include two protected virtual machines. You need to delete the Recovery Services vault. What should you do first?

To delete a Recovery Services vault, you must first stop protection and delete the backup data for all protected items within it. Stopping the backup of each backup item is the initial step because it releases the association between the vault and the protected resources. After stopping backup, you will then be able to delete the backup data, which is a prerequisite for vault deletion. Deleting the backup data directly without stopping the backup first is not possible. Modifying disaster recovery properties or locks of virtual machines is irrelevant to deleting the Recovery Services vault itself; these actions pertain to the virtual machines' configurations, not their backup status within the vault.