You must distribute a new iOS app to a private distribution group that contains both provisioned and unprovisioned devices using Visual Studio App Center. What action should you take?

To distribute an iOS app to a private group with both provisioned and unprovisioned devices via App Center, you must select "Register devices and sign my app." This option allows App Center to automatically handle the provisioning profile updates by registering new devices with Apple's Developer Portal and then re-signing the app with the updated profile, ensuring all devices can install and run the app. "Create an active subscription in App Center Test" is incorrect because App Center Test is for automated UI testing, not for app distribution. "Add the device owner to the organization in App Center" is incorrect as adding a user to an organization grants access to App Center features, but doesn't solve the device provisioning challenge. "Create an unsigned build" is incorrect because iOS apps require signing with a valid provisioning profile and certificate to be installed on any device, even for private distribution.