Which of the following statements are true about IS-IS addressing? (Select two.)
A . Routers within an area must use unique area addresses.
B . The area address is used in Level 1 routing.
C . The system ID identifies the area.
D . The system ID for Level 1 routers must be unique within an area.
E . The system ID for Level 2 routers must be unique within the whole domain.
Answer: DE