Q212. In the network shown in the figure, the interconnection lines between RT1, RT2, RT3, RT4 and RT5 are all Gigabit Ethernet lines, running OSPF, and routing interconnection after publishing the corresponding network segments. The routers all run the PIM SM protocol, and the RP is connected to the receiver on RT4, and IGMP is enabled on the corresponding interface. When the multicast meteor initially forwarded along the RPT meets the conditions for switching to the SPT, which of the following routers will receive the (S, G) join message? (Multiple choice)