What must an OSPF router do to ensure nonstop routing should a standby member take over as commander when the original VSF commander fails?

What must an OSPF router do to ensure nonstop routing should a standby member take over as commander when the original VSF commander fails?
A . It must run the shortest path first algorithm.
B . It must participate in a new election for the Designated Router.
C . It must initiate a graceful restart.
D . It must re-establish adjacency with its Designated Router.

Answer: C