You are designing the DNS zone to support the Active Directory domain for Contoso.Ltd. Which two actions should you perform?（）

• A、Create ad.contoso.com as a standard primary DNS Zone.  
• B、Create ad.contoso.com as an Active DirectoryIntegrated DNS Zone.
• C、Enable only authorized client computers to update DNS.  
• D、Configure a zone transfer between the DNS server at the ISP and the DNS servers at Contoso.Ltd.