You have 200 Azure virtual machines. You create a recovery plan in Azure Site Recovery to fail over all the virtual machines to an Azure region. The plan has three manual actions. You need to…

An Azure Desired State Configuration (DSC) virtual machine extension is primarily used for configuring and managing the state of virtual machines, not for executing arbitrary automation steps within a recovery plan workflow.

Azure Automation runbooks are designed for automating tasks across Azure and on-premises environments, and they can be directly integrated into Azure Site Recovery recovery plans to execute pre-failover, post-failover, or custom actions during a disaster recovery event.

An Azure PowerShell function is a serverless compute service; while it can execute PowerShell scripts, it's not directly integrated into Azure Site Recovery recovery plans as a mechanism for automated actions in the same way an Azure Automation runbook is.

A Custom Script Extension is deployed to individual virtual machines to execute scripts directly on them, which is not suitable for orchestrating actions across 200 VMs as part of a centralized recovery plan.