Which two options about PIM-DM are true? (Choose two.)
A.
PIM-DM initally floods multicast traffic throughout the network.
B.
In a PIM-DM network, routers that have no upstream neighbors prune back unwanted traffic.
C.
PIM-DM supports only shared trees.
D.
PIM-DM uses a pull model to deliver multicast traffic.
E.
PIM-DM cannot be used to build a shared distribution tree.