Refer to the exhibit. All multilayer switches are running PIM dense mode. Recipient A and Recipient B are sending IGMPv2 joi n messages to their respective multilayer switches. Which statement is true?（）

A.The Multicast Server is the root of the multicast tree. Switches 1, 3, 4, and 5 will participate in the multicast tree once pruning has taken place.

B.The Multicast Serv er is the root of the multicast tree. Switches 4 and 5 will participate in the multicast tree once pruning has taken place.

C.Switch 3 is the root of the multicast tree. Switches 3,4, and 5 will participate in the multicast tree once pruning has taken  place.

D.Switch 3 is the root of the multicast tree. Switches 1,3,4, and 5 will participate in the multicast tree once pruning has taken place.

E.Switch 1 is the root of the multicast tree. Switches 1,4, and 5 will participate in the multicast tree once pruning has taken place.

F.Switch 1 is the root of the multicast tree. Switches 1,3,4, and 5 will participate in the multicast tree once pruning has taken place.