WideAreaNetwork(WAN)isacomputernetworkthatcoversabroadareA.Whichstatementiscorrectforwide-areanetwork(WAN)?（） A: Limitedinasinglebuilding,agroupofbuildings,orevenasingleroom B: Crossesmetropolitan,regional,ornationalboundaries C: Encompassesanentirecityormetropolitanareaandconnectsmultiplelocal-areanetworks(LANs) D: Connectsclientdeviceswirelessprotocol