You are the network administrator for your company. The network consists of a single Active Directory domain. All servers run Windows Server 2003. All client computers run Windows XP Professional.You install Windows Server Update Services （WSUS） on a network server named Server1. When you attempt to synchronize Server1 with the Windows Update servers， you receive an error message. You open Internet Explorer and verify that you can communicate with an external Web site by using the proxy server. You need to ensure that Server1 can communicate with the Windows Update servers. What should you do on Server1？（）

A. Restart the IIS administration tool.
B. Configure the Internet Explorer settings to bypass the proxy server.
C. In the WSUS options， configure authentication to the proxy server.
D. Install the ISA Firewall Client.