I do think "what's it like to be a rock" is a sensible question almost regardless of the definition. I guess in the emergent view the answer is "not much". But anyhow this view (a) also allows for us to reconcile consciousness of an agent with the fact that the agent itself is somewhat an abstraction. Like one could ask, is a cell conscious & is the entirety of the human race conscious at different abstraction scales. Which I think are serious questions (as also for the stock market and for a video game AI). The explanation (b) doesn't seem to actually explain much as you state so I don't think it's even acceptable in format as a complete answer (which may not exist but still)