What is causing the problem?
A. The R3 router ID is configured on R4.
B. There is an OSPF hello and dead interval mismatch.
C. There is a Layer 2 issue; an encapsulation mismatch on serial links.
D. There is an area ID mismatch.
Answer:D
What is causing the problem?
A. The R3 router ID is configured on R4. B. There is an OSPF hello and dead interval mismatch. C. There is a Layer 2 issue; an encapsulation mismatch on serial links. D. There is an area ID mismatch.
Explanation: Explanation/Reference: