A.The IOS default is for a last-hop router to trigger a switch to the shortest path tree as soon as a new source is detected on the shared tree.
B.The IOS default is for every one of the routers on the shared tree to trigger a switch to the shortest path tree as soon as a new source is detected on the shared tree.
C.The default behavior of switching to the shortest path tree as soon as a new source is detected on the shared tree can be disabled by setting the value in the ip pim spt-threshold command to "infinity."
D.The default behavior of switching to the shortest path tree as soon as a new source is detected on the shared tree can be disabled by setting the value in the ip pim spt-threshold command to "zero."