Which three potential issues can cause an OSPF adjacency to not come up?

A.	wrong area configured on OSPF peers
B.	wrong authentication key configured on OSPF peers
C.	different OSPF instance numbers configured on OSPF peers
D.	different OSPF instances and VRFs configured with the command: router ospf <number1> vrf <number2>
E.	having the no passive-interface statement configured for the interfaces on which OSPF adjacencies are expected to form
F.	Layer 2 connectivity problems on the shared medium of the participating OSPF-enabled routers