Right now the only supported way to use Netflix is to use Google Chrome, as the second answer recommends. Firefox 49 (due next month) also allows for native Netflix. The accepted answer recommends a PPA and installing WINE, and the netflix-desktop package only even supports up to 15.04
I have always understood the checkmark as "this is what solved it for me". Therefore, if the OP solved their problem with that answer, it should be accepted.
There is a difference between an accepted answer and the "best" answer. Sometimes they are the same, sometimes they aren't.
By the way, the specific question asks "how" to watch Netflix on Ubuntu. There is not a single valid answer, but that doesn't mean the accepted one is incorrect.
The most correct answer was being eclipsed by an incorrect answer. Now that previously incorrect answer has been updated and that kludge has been partially fixed. I say partially fixed because the Netflix topic has popped up again today in this question: Netflix not working in Firefox, how to fix?.