Your network consists of a single Active Directory domain.You have a DHCP server that runs Windows Server 2003 Service Pack 2 （SP2）. All client computers run Windows XP Service Pack 3 （SP3）.A user named User1 reports that when she starts her computer， she receives a duplicate address error message.You confirm that her computer is configured as a DHCP client.You need to ensure that User1 receives a unique IP address from the DHCP server. What should you do on the DHCP server？（）

A. Reconcile the scope.
B. Create a superscope.
C. Enable conflict resolution.
D. Increase the number of IP addresses available in the scope.