You have a DNS server named Server1 that runs Windows Server 2003 Service Pack 2 (SP2). Server1 hosts a primary zone for contoso.com. On Server1, you update the host (A) record for server2.contoso.com to have a new IP address. On Server1, you run Ping server2.contoso.com from a command prompt and the old IP address for Server2 is returned. You need to ensure that the new IP address for Server2 resolves correctly on Server1. What should you do?（）
- ARun Nbtstat CR.
- BRun Ipconfig /flushdns.
- CRestart the DNS Server service.
- DOpen the DNS snap-in， right-click on the server and click ClearCache.