What are two reasons for an OSPF neighbor relationship to be stuck in exstart/exchange state? (Choose two.)

What are two reasons for an OSPF neighbor relationship to be stuck in exstart/exchange state? (Choose two.)
A . There is an MTU mismatch.
B . There is an area ID mismatch.
C . Both routers have the same OSPF process I
E . Both routers have the same router I
G . There is an authentication mismatch.

Answer: A, D