"Which one is the best" is obviously a question format, so it makes sense that " which one the best is " should be the correct form. This is very good instinct, and you could even argue that the grammar is good, but at best it's unnatural.
Some people say a dog=one, dogs=ones, the dog=the one=that, and the dogs=the ones=those. It's a rule of thumb, but what I found was that this is not always correct.
The "one" could imply that of the alternates only ONE choice is possible, or permitted. "Which" alone could indicate several choices from the set of alterates could be selected in various combinations. Of course, speakers are often very imprecise about their meanings & intentions when saying "which" or "which one". Usually the context makes it clear if the choices are mutually exclusive or not ...
A thousand bucks isn't "go buy a yacht" money. But it's also not nothing -- and what you do with it today can matter more than you'd think. I've been writing about personal finance for years, and the ...
One-to-one is used when you talk about transfer or communications. You may use one-to-one when you can identify a source and a destination. For eg., a one-to-one email is one sent from a single person to another, i.e., no ccs or bccs. In maths, a one-to-one mapping maps one element of a set to a unique element in a target set. One-on-one is the correct adjective in your example. See Free ...
Which one is grammatically correct or better? I have two assignments, One of them is done. I have two assignments, One of which is done. I watched a video tutorial that the teacher said the ...