Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two)

Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two)
A . It is locally significant.
B . It is globally significant.
C . It is needed to identify a unique instance of an OSPF database.
D . It is an optional parameter required only if multiple OSPF processes are running on the router.
E . All routers in the same OSPF area must have the same process ID if they are to exchange routing information.

Answer: AC

Explanation:

https://learningnetwork.cisco.com/thread/6248

They are locally significant only, and have no bearing on the structure of any OSPF packet or LSA update. So you can have a separate process-id on every single router in your network if you so desire!