Which three statements about the designated router election in IS-IS are true? (Choose three.)

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Which three statements about the designated router election in IS-IS are true? (Choose three.)

A. If the IS-IS DR fails, a new DR is elected.
B. The IS-IS DR will preempt. If a new router with better priority is added, it just becomes active in the network.
C. If there is a tie in DR priority, the router with a higher IP address wins.
D. If there is a tie in DR priority, the router with a higher MAC address wins.
E. If the DR fails, the BDR is promoted as the DR.
F. The DR is optional in a point-to-point network.