household bleach has a neutral pH, whereas drain cleaner contains lye (very alkaline) and can cause liquefactive necrosis (ulcerations on the lips, etc.); the other options seemed more benign to me, but I definitely guessed between drain cleaner and bleach
source: https://pedclerk.bsd.uchicago.edu/page/caustic-ingestions
submitted by โseagull(1933)
I'm relatively sure that most people were 50:50 between bleach and drain cleaner.