You need to provide a user with the minimal access needed to perform maintenance on the Session Hosts that includes removing the session hosts from the pool and changing the drain mode. Which role would you provide to the user?

Answer options:

A.User Session Operator
B.Session Host Operator
C.Host Pool Contributor
D.Desktop Virtualization Contributor

Correct Answer: B 
The session Host operator role allows the user to view and remove the session hosts, even change drain mode. This role does not allow you to add session hosts through the Azure portal as this role doesn`t have the write permissions for host pool objects.
Option A is incorrect. The User Session Operator allows you to send the messages, disconnect the sessions, and use the "logoff" function to sign sessions out of the session host. This won`t meet the requirements.
Option B is correct. The session Host operator role allows the user to view and remove the session hosts, even change the drain mode.
Option C is incorrect. The host pool contributor role will provide the users with more rights than required.
Option D is incorrect. Desktop Virtualization Contributor will also provide the user with more rights than required.
Reference: 
To know more about Built-in roles for Azure Virtual Desktop, please visit the below-given link: 

https://docs.microsoft.com/en-us/azure/virtual-desktop/rbac?WT.mc_id=AZ-MVP-5004159