What specific feature in Windows 2016 allows the management of a running Hyper-V VM from a Hyper-V host PowerShell prompt?

The correct answer to the following question will be "PowerShell Direct".

Explanation:

PowerShell Direct is indeed a new security feature in Windows Server 2016 that allows you to create a direct localized PowerShell connection with a certain VM (virtual machine) operating on a Hyper-V host, whereas communication is built not through a network, but via an internal virtual machine bus.

Main requirements for the use of Powershell Direct are as follows:

You can use Windows Server 10 or 2016 as a Hyper-V host OS. The VM guest must be run on that same type that offers a local connection. You need to enter the login information of the account in this VM to connect to the guest OS.

Therefore, PowerShell Direct is the right answer.