The next two-three years will determine if it's B or C, frankly.
The quality of various D&D-based multimedia products - games, TV, movies - will have a huge impact. And Wizards needs to be ready to leverage their brand, not just D&D, if they want staying power. I suspect their bizarre logo change is part of this. They're going hard with the AAA games studios and hook-ups with various studios and so on to push into that digital space. The first in-house effort is looking increasingly "hmmm", unfortunately - Baldur's Gate: Dark Alliance. I think that's going to be, at best, a forgettable 6/10 AA game instead of the memorable 8/10+ AAA game it absolutely needed to be.
Based on D&D's history I tend to suspect the other multimedia stuff will also not do great. I hope it does awesome - best chance is with the TV show I suspect.
So C seems more likely.
However, regardless, as others have pointed out, the sheer number of people who will have played D&D will have an impact, and will probably boost the entire RPG industry for at least a decade, and people's kids are playing it, too, and you can pretty much bet that in 20+ years from now that will lead to another revival of some form. Be interesting to see if Wizards still exists and has the licence then of course. I suspect that they will not on either count, because some new management wave will have come in at Hasbro during the era when sales are declining, and broken them up/sold them off.
EDIT - The only way we haven't reached peak D&D is if Wizards releases a significantly-better-than-DNDBeyond digital space replete with a VTT so good it can barely be called a VTT, and has a very favourable pricing model, and does so in the next few years.