You are a network administrator for your company. The network consists of a single Active Directory domain. All servers run Windows Server 2003. Client computers run Windows XP Professional， Windows 2000 Professional， or Windows NT Workstation. All client computers are configured with default settings.A server named Server1 functions as a DHCP and DNS server. All client computers are configured to use Server1 for name resolution. All DNS zones on Server1 are enabled for DNS dynamic updates. The company’s written security policy states that， when possible， the computer account for each client computer should be the owner of its own DNS host record.A server named Server18 contains antivirus server software. Server18 must be able to contact client computers by using fully qualified domain names （FQDNs） to propagate virus definition updates.You need to ensure that Server18 can resolve FQDNs for all client computers on the network. Which option should you modify on Server1？（）

A. the Dynamically update DNS A and PTR records only if requested by the DHCP clients check box
B. the Always dynamically update DNS A and PTR records check box
C. the Discard A and PTR records when lease is deleted check box
D. the Dynamically update DNS A and PTR records for DHCP clients that do not request dynamic updates （for example， clients running Windows NT 4.0） check box