Which of the following describe the process identifier that is used to run OSPF on a router? (Choose two.)（）
- AIt is locally significant.
- BIt is globally significant.
- CIt is needed to identify a unique instance of an OSPF database.
- DIt is an optional parameter required only if multiple OSPF processes are running on the router.
- EAll routers in the same OSPF area must have the same process ID if they are to exchange routing information.