Your network consists of a single Active Directory domain that has three Active Directory sites. Each site contains two Active Directory domain controllers.  All domain controllers run Windows Server 2003 Service Pack 2 （SP2）. All domain controllers have Windows Support Tools installed. You need to verify the replication status of Active Directory.  Which tool should you use？（）

• A、Active Directory Sites and Services
• B、Nltest.exe
• C、Network Monitor
• D、Replmon.exe