by RonPurewal Sat Sep 05, 2015 1:44 pm
'sufficient' means that the question is narrowed down to a SINGLE, UNIQUE answer.
if there's more than one possible answer—regardless of whether that's 2 answers, 200 answers, or infinitely many answers—then that's 'not sufficient'.
think about it like a criminal trial: you either know who committed the crime, or you don't.
if you can narrow it down to ONE person, then ... you know who committed the crime ('sufficient').
if you have two thousand possible culprits, then ... you don't know who committed the crime ('not sufficient').
if you narrow the possibilities down to just two suspects, then ... well, you STILL don't know who committed the crime (still 'not sufficient').