Until a Best Answer has been selected, the question is still considered unresolved. And some folks either don't get answers they like, or can't be bothered to select a best from those they got.
Select as Best AnswerUndo Best Answer
The person who asked the question hasn't selected any of the answers as a "Best Answer".
It hasn't had a correct answer. To be *answered* it has to have that little blue answered sign.
Actually the criterion is not necessarily "correct" but "querant likes this answer, and has made the effort to say so."(I think the Instructables crew has gone thru and cleaned up a few of these pending questions when it's obvious the querant isn't going to... but obviously not many.)
The person that posted the question hasn't marked it as being answered.