Yeah, when I realized that Ravel accepted other answers it was like discovering Santa Clause wasn't real. "Regret" was the answer that made by far the most sense given TNO's narrative. Anyone who played and didn't choose "regret" was wrong.
"Regret" is the answer of the original incarnation, if that's any comfort.
Part of the point, I think, is that there isn't a single correct answer. The answer the Nameless One chooses is the answer which is capable of changing him.
Well, technically, if you 'believe' that 'regret' is the answer then it's correct!