This is new.
Maybe should use the suggestedAnswer with the answer that has got more “likes” 
on topic when answerCount is > 0 and doesn’t have any answer with “solved” mark. 
Check Google Strutured Data for example here.
I edit and explain my point.
In many debates, many situations are investigated and posed (which are answers) but do not constitute a solution to the subject in question.
Following the idea that commented @ced, a subject of 10 answers for example, some of those answers are valued with at least three “likes” should become “suggestedAnswer”.