You need to configure a host pool to automatically assign users to Virtual Machines. Complete the following PowerShell cmdlet to meet the goal. 
_______________ -ResourceGroupName <resourcegroupname> -Name <hostpoolname> -PersonalDesktopAssignmentType Automatic

Answer options:

A.Update-AzWvdHostPool
B.New-AzRoleAssignment
C.New-AzWvdHostPool
D.Update-AzRoleAssignment

Correct Answer: A 
The following cmdlet helps in configuring a host pool to automatically assign users to Virtual Machines: 
Update-AzWvdHostPool -ResourceGroupName <resourcegroupname> -Name <hostpoolname> -PersonalDesktopAssignmentType Automatic
Option A is correct. Update-AzWvdHostPool is the right cmdlet to configure a host pool to automatically assign users to Virtual Machines.
Option B is incorrect. New-AzRoleAssignment is used to assign a user to the personal desktop host pool.
Option C is incorrect. New-AzWvdHostPool is not the right command to meet the desired goal.
Option D is incorrect. Update-AzRoleAssignment won’t help in configuring a host pool to automatically assign users to Virtual Machines:
Reference: To know more about configuring the personal desktop host pool assignment type, please visit the below-given link: 

https://docs.microsoft.com/en-us/azure/virtual-desktop/configure-host-pool-personal-desktop-assignment-type