You have an Azure AD tenant named contoso.com and an Azure virtual network named VNET2. To VNET2, you deploy Azure AD DS (Azure Active Directory Domain Services) managed domain named liwareinc.com
To VNET2, you decide to deploy a WVD host pool named Pool2. 
You need to ensure that you can deploy Windows 10 Enterprise host pools to Pool2. 
What would you do first?

Answer options:

A.Change the settings for liwareinc.com DNS Zone
B.Change the DNS settings for VNET2
C.Add a custom domain name to contoso.com
D.Implement Azure AD Connect cloud sync

Correct Answer: B 
After Azure AD DS is successfully deployed, you should configure the VNET to allow other connected virtual machines and applications to utilize the managed domain. To provide this connectivity, you should modify the DNS server settings for your VNET to point to the two IP addresses where the managed domain is deployed.
Option A is incorrect. You don’t need to change the settings for liwareinc.com DNS Zone.
Option B is correct. Changing the DNS settings for VNET2 will enable you to deploy Windows 10 Enterprise host pools to Pool2.
Option C is incorrect. You don`t need to add the custom domain name to contoso.com.
Option D is incorrect. Implementing Azure AD Connect cloud sync won’t help in meeting the goal.
Reference: 
To know more about how to create and configure an Azure Active Directory Domain Services managed domain, please visit the below-given link: 

https://docs.microsoft.com/en-us/azure/active-directory-domain-services/tutorial-create-instance