I tried to keep the main options realistic ones, some are based on rumours (IO Interactive, Turtle Rock, Typhoon Studios), some are based on educated guesses around previous rumours (Bluepoint Games, Asobo Studios), some based on previous acquisition attempts (Moon Studios) and they all fit into what Microsoft is looking for in terms of studio size, nothing too crazy like that Platinum rumours.
I only included 4A Games because I needed to pad the poll out a little and because it seems to always be a more realistic fan favourite option on people's lists around places like Era, I still have one space left but I don't know what to fill it with, maybe Studio MDHR? There's so many small-mid sized studios to pick from that are possibilities.
For 'Open a Studio' that'll be a case like The Initiative, If you'd like you can post the genre/location of the studio, I know some of you would love a Japanese studio, I don't think it's really realistic that they'd buy one, I don't really think it's realistic that they'll open one either but I do think it's more realistic than buying one so I gave the option to pick, can be a Western studio, Eastern Studio, etc.
My list: 4A Games > Moon Studios > Open a Studio > Bluepoint Studios > IO Interactive > Asobo Studios > Turtle Rock > Typhoon Studios.
Honestly I'd be happy with any of them options though Tbh, some are better than others but I wouldn't say any of them would be a bad purchase.