Say Answer A is upvoted by most-users. B ranks next at half the no. of upvotes and C at one-third of upvotes as A.
I do like A for its technical validity, historical accuracy and relevance. However, the question had been edited quite a bit and I find C seeks to answer the spirit of the question (the reason OP had in mind) as captured in the original question that existed prior to edits.
I want to give the 'Accept' status to C. Because, I think, anyway A has its place of glory by being the most voted and will be noticed. By marking C as the accepted answer, I might get more readers from future audience to read it, to see its relevance to the question(well, as I see it).
So, can I upvote unpopular answer, that is not entirely incorrect and not the best either ?