You have just completed an OSPF implementation. While executing your verification plan, you determine that R1 is not able to establish full OSPF adjacency with R2. The show ip ospf neighbor comman d output on R1 shows that R2 is stuck in the INIT state. What could be the cause of this problem?（）

A. DR and BDR election errors between R1 and R2.
B. The R2 router has not received the OSPF hello packets from the R1 router.
C. Mismatched interface ma ximum transmission unit (MTU) configuration between the R1 and R2.
D. Mismatched OSPF hello interval configuration between the R1 and R2
E. Corrupted LSAs exchanges between the R1 and R2.