Explanation:

Box 1: 4
Scenario: the Azure Resource Manager template that will be used to provision the production application servers.
Ensure that each production application server has four 1-TB data disks.
Box 2: Standard_LRS
Scenario: Minimize costs whenever possible.
Box 3: contoso.onmicrosoft.com
The network contains an on-premises Active Directory domain named ad.contoso.com.
The Initial domain: The default domain (onmicrosoft.com) in the Azure AD Tenant. For example, contoso.onmicrosoft.com.
References:
https://docs.microsoft.com/en-us/azure/active-directory/hybrid/plan-connect-userprincipalname