Your Windows Server 2003 environment consists of a single Active Directory directory service forest with multiple domains. The forest functional level is set to Windows 2000 Server. Your company has a main office and four branch offices. Each office has two domain controllers. The domain controllers in the main office are global catalog servers.  In the branch offices， searches for some printers in Active Directory are slow. You need to improve the performance of Active Directory printer searches in the four branch offices.  What should you do？（） 

• A、 Enable universal group membership caching in each branch office.
• B、 Increase the number of domain controllers in each branch office.
• C、 Add global catalog services to each branch office.
• D、 Upgrade the forest functional level to Windows Server 2003.