What is the Router-ID of OSPFv3?

As shown in the figure, the network has caused a loop because STP is not enabled. Which of the following phenomena may be caused? (Multiple choice)

(Drag and drop) As shown in the figure, there is a message containing three-layer label headers. Please select the corresponding values of the X, Y, and Z fields in the figure. (Decimal)

(Connection question) Please correspond the alarm level with the importance of the fault and the countermeasures. (Multiple choice)

If the Sticky MAC function of the interface is enabled, what is the number of MAC addresses learned by the interface by default?