Rather like the Mile High Club, I don't believe the Three Commas Club actually exists as an organisation (which the question at least implies it does). There are a few references to it on the Internet, but none that say "this is its Secretary and these are its headquarters".
There is a Three Commas Club group on Facebook, which calls itself "a movement that exists to empower The Entrepreneurs of today and create a world where entrepreneurship is celebrated." There's an American clothing brand called Three Commas, founded by billionaires Mark Cuban (owners of the Dallas Mavericks NFL franchise) and Michael Chaffin (business manager of the rap artiste Nelly).
In other words, 'the Three Commas Club' is just a metonym. It might have helped if the question had mentioned this. Then again, it might not!
This is the kind of thing that once you've heard it you'll never forget it; but if you haven't heard it, you'd do extremely well to guess it. In other words, the kind of quiz question that only someone who's heard it in a quiz before is going to get right. And that (IMHO) is never a good thing.
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