C) is only a clear indication under a too-short idea of what "short-term" means for a company like Google.
For large corporations 9-12 months is short term, and 1-2 years not too long to fall into that category either.
Critical points in Stadia's success are coming up in next few months. Pre orders for one of the most popular sports games in the world, releasing 100 games by the end of the year-- a benchmark they're behind on-- and a precarious expansion into Mexico.
These should show results before the end of the year, 5 months from now. If they underperform then I think it's extremely possible that a service cancellation would be announced within 9-12 months.
In the other hand they had no option except C, not really. Anything else would have as good as killed the service anyway. A) or B) would mean updated articles and new headlines would read "Google Won't Deny Rumours of Stadia's Death". B) would be the worst: "Google won't commit to further Stadia Support".
If they might kill it sometimes in the short term of 9-12 months but haven't made a final decision yet then C) was their only option regardless of the truth of any of those. C) conveys the least information (I'd say none) of those options because it does not provide any way to evaluate the truth of the statement unless you take Google at it's word. And yet whether or not we can take them at their word is exactly the thing in question.