For which reason can two devices fail to establish an OSPF neighbor relationship? 

Answer options:

A. The two devices have different process IDs
B. The two devices have different network types
C. The two devices have different router IDs
D. The two devices have the same area ID

B

Reference: https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13699-29.html