Q12 Multiple choice Mark for later Which two statements about IS-IS are correct? (Choose two.) Select all that apply. A Level 1 intermediate systems exchange routing information with Level 1 intermediate systems on other IS-IS areas. B An IS-IS router sets the attached bit in the PDUs it sends to a Level 1 area to indicate that it is a backbone router. C A Level 1 router can only form adjacencies with other Level 1 routers. D Level 2 routers can form adjacencies with either Level 1 or Level 2 routers. Correct answer