You observe that a router is using an unusually high amount of CPU cycles. You determine
that continuous SPF calculations in OSPF are being performed. What are two reasons for
this problem? (Choose two.)

A.
An OSPF adjacency is flapping.

B.
There are duplicate router IDs within the OSPF area.

C.
The interface MTU is mismatched between the OSPF neighbors.

D.
The wrong authentication keys between the OSPF neighbors are used.