One million is way too many. So I'll go with the brain booster.
Would you rather be stuck underground for 1 year or stuck in the sky for 1 year? (In both circumstances you have everything you need to live.)
depends. In the sky scenario, am I in a suspended room? Am I flying? Am I falling continuously for a whole year and all my necessities are falling with me at the same velocity? Am I in the top room of a sky scraper with no way of getting down?
Where underground would I be? A country pron to earthquakes? Or am I safe from natural disasters? Is ventilation pumped from the surface or brought down in pressurized cannisters? Or perhaps its recycled?
In both scenarios, what luxuries am I afforded? What constitutes "everything I need to live"? Are we talking just food and water? Or is there enrichment and whatnot for mental health. Is my social health included in this consideration? How big of a living space am I in?
I think the safest bet here would be underground as there is less to be assumed here. Also. At my 5'8" stature I will get to live out my ideal dwarven lifestyle where I can pretend to dwell in the mines of a mountain.
Would you rather be born a Dwarf or an Elf (in your preferred fantasy world/franchise)?
(Yes I will judge you on your answer)