Living, dead... and as Taura said, not a who but a what. "Right... riddles tend to rely on metaphors or wordplay. It's easy to start picturing people when you think about the living or the dead, but..." It could easily be something entirely different. Maybe even something that was never alive in the first place, but could be thought of as such...

When Goku chimed in, sounding confused, Rita shot a glare at him. "I said be quiet. Do you want to screw this up?" It didn't even matter if he knew what was going on or not, just so long as he could shut up long enough for the rest of them to work out the puzzle.

... Damn it, now she lost her train of thought.