If routers in a single area are configured with the same priority value, what value does a router use for the OSPF Router ID in the absence of a loopback interface?

Question: If routers in a single area are configured with the same priority value, what value does a router use for the OSPF Router ID in the absence of a loopback interface?
[A].

The lowest IP address of any physical interface

[B].

The highest IP address of any physical interface

[C].

The lowest IP address of any logical interface

[D].

The highest IP address of any logical interface

Answer: Option B

Explanation:

At the moment of OSPF process startup, the highest IP address on any active interface will be the Router ID (RID) of the router. If you have a loopback interface configured (logical interface), then that will override the interface IP address and become the RID of the router automatically.