I don't think any can be conclusively ruled out, but if we start to weight each candidate by things such as
* motive(am I gaining/losing leverage by this?),
* ability (can I actually do/help/enable this action?)
* consequence (can I get away with it? Can I muddle it and make people get along with it?)
* context (a war is going on, but so is internal politics; does my context push me for this action?)
I think probably more than half could be reasonably ruled out, depending on how each of those were weighted. And we could probably reason about the accomplices too
The issue here is that the state with the most motive (Ukraine) is one that most are agreed did not have the opportunity to actually conduct the attack. Nobody else has a strong motive. The US had already achieved what it could have hoped to achieve months before the pipeline explosion. Russia's plausible motive assumes a certain amount of strategic insanity mixed with thuggery. Everybody else's motive more or less rests on making a political statement that they haven't been making in public.
* motive(am I gaining/losing leverage by this?),
* ability (can I actually do/help/enable this action?)
* consequence (can I get away with it? Can I muddle it and make people get along with it?)
* context (a war is going on, but so is internal politics; does my context push me for this action?)
I think probably more than half could be reasonably ruled out, depending on how each of those were weighted. And we could probably reason about the accomplices too