You have Microsoft 365 Business Standard and 100 Windows 10 Pro PCs, and you purchase Microsoft 365 E5. To upgrade those devices to Windows 10 Enterprise with the least administrative effort, which upgrade method should you use?

Subscription Activation is the most efficient method for upgrading Windows 10 Pro to Enterprise in this scenario. Since you have Microsoft 365 E5, which includes Windows 10 Enterprise E3 or E5 rights, Subscription Activation automatically upgrades eligible devices without needing new product keys or reinstallation. This process is seamless and requires minimal administrative effort. Windows Autopilot is primarily for device provisioning and deployment, not for in-place OS edition upgrades of existing devices. A Microsoft Deployment Toolkit (MDT) lite-touch deployment would involve re-imaging or a more complex upgrade process, requiring significant administrative overhead. An in-place upgrade using Windows installation media also requires more manual intervention and time per device compared to Subscription Activation.