When the OSPF opeational state is down, what does it mean?

a$.$ Routers exchange DBD packets

b$.$ No hello packets received

c$.$ Routers have converged databases

d$.$ Used to elect a DR and BDR on ethernet link

e$.$ Hello packets are received that contain the sending router$$s ID

f$.$ Negotiate master$/$slave relationship

g$.$ LSRs and LSUs are used to gain additional route information