Which two statements about the OSPF Router ID are true? (Choose two.)

Every OSPF router generates a Type 1 Router LSA to describe its links and their states; the Router ID embedded in that LSA identifies which router originated it, making the Router ID the source identifier for Type 1 LSAs.

OSPF Router IDs must be unique per router within a domain; having the same Router ID on multiple routers causes database corruption and adjacency failures.

By default, OSPF prefers the highest loopback IP, not the lowest; if no loopback exists, it uses the highest active physical interface IP.

When no Router ID is manually configured, Cisco IOS selects the highest IP address assigned to any loopback interface as the OSPF Router ID, because loopbacks are stable and never go down due to physical failures.

OSPF Router IDs are always IP addresses derived from interface addresses or manual configuration - MAC addresses are never used in OSPF Router ID selection.