单项选择题

A. Configure each switch with PIM sparse mode and a separate instance of PIM dense mode.Specify switch 1 as the root for the RPI Multicast Server. Specify switch 2 as the root for the CMU Multicast Server.
B. Configure each switch with PIM sparse mode and a separate instance of PIM dense mode. Leave each multicast server as the root of its own multicast tree.
C. Configure each switch with PIM sparse - dense mode. Configure switch 3 as a ren dezvous point for the RPI multicast stream.
D. Configure each switch with PIM sparse mode and a separate instance of PIM dense mode.Allow the switches to elect their own root for each multicast tree.
E. Configure each switch with PIM sparse mode.
F.  Configure each switch with PIM dense mode.