Refertotheexhibit.S0/0onR1isconfiguredasamultipointinterfacetocommunicatewithR2andR3inthehub-and-spokeFrameRelaytopology.Whiletestingthisconfiguration，atechniciannotesthatpingsaresuccessfullyfromhostsonthe172.16.1.0/24networktohostsonboththe172.16.2.0/25and172.16.0.2.128/25networks.However，pingsbetweenhostsonthe172.16.2.0/25and172.16.2.128/25networkarenotsuccessful.Whatcouldexplainthisconnectivityproblem？（）

A.Theipsubnet-zerocommandhasbeenissuedontheR1router.

B.TheRIPv2dynamicroutingprotocolcannotbeusedacrossaFrameRelaynetwork.

C.SplithorizonispreventingR2fromlearningabouttheR3networksandR3fromlearningaboutR2networks.

D.The172.16.2.0/25and172.16.2.128/25networksareoverlappingnetworksthatcanbeseenbyR1,butnotbetweenR2andR3.

E.The172.16.3.0/29networkusedontheFrameRelaylinksiscreatingadiscontiguousnetworkbetweentheR2andR3routersubnetworks.