Your company has a main office and a branch office. Your network contains a single Active Directory domain. An Active Directory site exists for each office. All domain controllers run Windows Server 2008  R2.   You plan to modify the DNS infrastructure.   You need to plan the new DNS infrastructure to meet the following requirements： èEnsure that the DNS service is available even if a single server fails èEncrypt the synchronization data that is sent between DNS servers èSupport dynamic updates to all DNS servers What should you include in your plan？（）

• A、Install the DNS Server server role on two servers. Create a primary zone on the DNS server in the main office. Create a secondary zone on the DNS server in the branch office.
• B、Install the DNS Server server role on a domain controller in the main office and on a domain controllerin the branch office. Configure DNS to use Active Directory-integrated zones.
• C、Install the DNS Server server role on a domain controller in the main office and on a Read-only domain Controller （RODC） in the branch office. Configure DNS to use Active Directory-integrated zones.
• D、Install the DNS Server server role on two servers. Create a primary zone and a GlobalNames zone on  the DNS server in the main office. Create a GlobalNames zone on the DNS server in the branch office.