You maintain a multi-tier web application hosted in production on Azure VMs. You have an ARM template for the VM configuration to test new features. You need a staging environment that minimizes Azure hosting cost, provisions VMs automatically, and uses the custom ARM template. Which approach meets these requirements?

The correct answer is to use Azure DevOps with Azure DevTest Labs. Azure DevTest Labs is specifically designed for creating and managing environments for development and testing, offering features like automatic shutdown policies to minimize costs and integration with ARM templates for consistent provisioning. Azure DevOps release pipelines can automate the creation and deletion of these lab environments, ensuring an efficient and cost-effective staging process. Using Azure CLI or PowerShell commands directly from Cloud Shell would require manual execution for creation and deletion, which doesn't meet the "provisions VMs automatically" requirement. Deploying to Azure Cloud Services is an older platform-as-a-service (PaaS) offering and doesn't directly address the need to provision and manage VMs using a custom ARM template in a cost-optimized staging environment.