You are a network administrator for A. Datum Corporation. The network consists of a single Active Directory domain named adatum.net. Users regularly browse the internal network and the Internet from their client computers. All Web and e-mail hosting for a separate DNS domain named adatum.com is outsourced to an ISP. All name resolution requests for adatum.com are resolved by the ISP. You have no administrative control over the DNS servers at the ISP. You cannot list the contents of adatum.com by using the nslookup command on the DNS servers at the ISP.A Windows Server 2003 computer named Server1 is configured with a primary zone for adatum.net. All root hints have been removed from Server1. All client computers refer to this DNS server for name resolution.You need to configure DNS resolution to ensure that all client computers can locate and access resources in adatum.net， adatum.com， and the Internet.   What should you do？（）

• A、Configure a secondary zone for adatum.com on Server1.
• B、Configure a primary zone for adatum.com on Server1.
• C、Configure conditional forwarding for adatum.com with the IP address of the DNS server at the ISP.
• D、Configure simple forwarding with the default settings with the IP address of the DNS server at the ISP.