Its much better than 50%. Is Iran being accused of supporting Shia or Sunni militants?Iran was accused of helping Al Kaida.They do not do that/Saudi did/
Iran was accused of helping ISIS.They were fighting them,and Lebannon was saved from ISIS by Iran supported Hezbollah.And ISIS was initially supported by USA.
So,it is at least 50% of chance that again Iran is framed for something made by Saudis.Or USA.Or Izrael.Or all of them.
If its the former, the chances rise a lot. If its the latter, the chances fall somewhat.
Considering the recent naval drama, the method of operation, and the locations and targets involved, chances are that it is them.
Note that Iran has already done a similar thing to a different tanker a year ago more officially, also for the sake of political show.
Iran seizes British tanker in Strait of Hormuz
A second tanker is now back on its way after it was boarded by armed guards in the Strait of Hormuz.
www.bbc.co.uk