YouhaveanExchangeServer2010organization.YouhaveagroupnamedGroup1thatcontains10，000members.YouneedtoensurethataninformativemessageisdisplayedwhenusersaddGroup1totherecipientlistofane-mailmessage.Whatshouldyoudo？（）

A.ConfigureaMailTip.

B.Createatransportrule.

C.CreateaSendconnector.

D.Configureanexpansionserver.