My concern is the last one, because I think it is a real risk that can sneak up on us, and has the potential to derail progress. Right now, we mine natural resources (and the biosphere) non-renewably, and build human innovation with the capital. This has lead to increasing levels of perceived progress and wealth. If we made our natural resource consumption sustainable, ostensibly human innovation could continue to build progress.
Unfortunately, ecosystems suffer tipping points, so there's very little warning of impending doom. Things look find until they're not. So, what can you do? Try to build wealth as efficiently as possible, and try not to destroy nonrenewables for wasteful reasons ...
So, to answer. If not (c), then (b). Endgoal is a space-borne species