Your network consists of a single Active Directory domain.You have a Web server named server1.contoso.com that runs Windows Server 2003 Service Pack 2 (SP2). Users access a Web site on Server1 by using the URL http://server1.contoso.com. Users also access the Web site on Server1 by using the URL http://192.168.1.10.You need to configure DNS to enable users to access the Web site by using the URL http://www.contoso.com. The solution must prevent the need to manually update DNS if the IP address of Server1 changes.  Which type of resource record should you create in DNS?（）

• A、alias (CNAME) 
• B、host (A) 
• C、host (AAAA) 
• D、host information (HINFO)