If World War III began today, which country is most likely to start it?

Saudi Arabia is the most likely country to mess things up, but Turkey is not far behind and the reasons are virtually the same, US and Russia are in the list because they are the torches that can be ignited, but they alone will not start a big war. China and India will always limit any conflict to regional scale and even retreat in case it goes beyond their expectations (even if it goes well for them) - they both depend on peace time more than on any imaginable spoils of any bigger war. There are countries like Israel, which start wars so often that nobody will care to join in and make one of these a world war...