Which of the following are true of both OSPFv2 and OSPFv3? (Choose two.)

A.
The method of choosing an OSPF router ID

B.
Verification checks that must be validated before two routers can become OSPF
neighbors

C.
Support for route tags

D.
Support for multiple instances per interface

Explanation:
OSPFv3 supports multiple OSPF instances per interface, whereas OSPFv2 does not. Also,
each version requires a different set of requirements be met before becoming neighbors,
most notably that OSPFv3 does not require neighboring OSPFv3 routers to be in the same
subnet.