I would observe that option c) happens today - its just that the parties
involved don't inform the InterNIC (becuase if you try to undertake
the transfer of title the InterNIC simply takes the address space away.
The picture is somewhat complex in so far as IP address space has
intrinsic value _as long as it is routeable_.
Given the interaction between the costs of renumbering, vs the cost of
establishing an entry in the routing tables, vs the cost of dynamic address
translation then its not obvious whether pricing policies should apply to
address space allocation, routing table entries or both!