You are a network administrator for your company. The network consists of a single Active Directory forest that contains three domains. The functional level of the forest and of all three domains is Window Server 2003. The company has a main office and 30 branch offices. Each branch office is connected to the main office by a 56-Kbps WAN connection. You configure the main office and each branch office as a separate Active Directory site. You deploy a Windows Server 2003 domain controller at the main office and at each branch office. Each domain controller is configured as a DNS server. You can log on to the network from client computers in the branch offices at any time. However， users in the branch offices report that they cannot log on to the network during peak hours. You need to allow users to log on to the network from branch office computers. You do not want to affect the performance of the branch office domain controllers. You need to minimize Active Directory replication traffic across the WAN connections. What should you do？ （）

A. Use Active Directory Sites and Services to enable universal group membership caching for each branch office site.
B. Use the DNS console to configure the branch office DNS servers to forward requests to a DNS server in the main office.
C. Use Active Directory Sites and Services to configure each branch office domain controller as a global catalog server.
D. Use the DNS console to configure the branch office DNS servers to use an Active Directory-integrated zone.