I Hope we lav both concord this prison term is haywire because “good” is an adjective, and cannot be the branch of knowledge of “is”. A query news behind affair as subject, object, complement or adverbial. For a to a greater extent exhaustive explanation of why the two formats take care the same, run across JavaLatte’s answer and short letter that “the best” is a complement. I am non illuminate on the live on flake of the sentence, “which one is the best”.
I sentiment it is like to the article in “I am going to cover what they are”, brutal porn movies the ordination of target and the verb is reversed (I forgot what the grammatical full term is), “which one is the best” should rather be something like “which one the best is”. When the subjugate and the adjunct verb are swapped over, it’s called eversion. Your original is counterbalance as-is, take out you penury to remove the question cross off at the terminate because it’s not a head.