YoudeployanExchangeorganization.AllserversintheorganizationhaveExchangeServer2010ServicePack1（SP1）installed.TheorganizationcontainstwoHubTransportservers.ThenetworkcontainstwoActiveDirectorysitesnamedSite1andSite2.EachsitecontainsoneHubTransportserver.EachsitehasadirectconnectiontotheInternet.Youneedtoconfiguremessageroutingfortheorganizationtomeetthefollowingrequirements
（1）E-mailmessagessenttoaSMTPdomainnamednwtraders.commustbedeliveredfromSite2.
（2）IfSite2isunavailable，e-mailmessagessenttonwtraders.commustbedeliveredfromSitel.
（3）E-mailmessagessenttoallotherSMTPdomainsmustbedeliveredfromSitelonly.
Whatshouldyoudo？（）
参考答案：D
