Who gets nuked first - the Middle East, China, Russia, or America?

Conventional wisdom says one of these locations will be ground zero for a nuclear attack and probably sooner than most would like to believe.

I could see a few different scenarios:

1. Russia gets backed into a corner after taking a military stand on Crimea and is stopped by an American coalition, making Putin feel like he has nothing to lose in an attempt to prove superiority

2. China moves in on Taiwan with non-military help from Russia and potentially assistance from North Korea. America fulfills is treaty obligations and steps in to defend Taiwan, first with recon and humanitarian assistance but then gets dragged into boots oj the ground assistance. China, too far committed by then, only steps up their game and Americans are killed. Thousands of marines are then deployed and Russia provides military assistance. The American navy sinks multiple Chinese and Russian submarines. Our overwhelming naval presence in the area along with a hundred thousand troops on the ground spirals China and Russia out of control and they feel backed into a corner. Not wanting to whimper out and retreat, they make an emotional last-ditch effort decision to launch a couple nukes at strategic targets in America or American territories.

3. A terror group in the middle east is transporting a nuclear weapon after purchasing it on the black market when it explodes.

4. Iran obtains lots of our advanced weaponry left behind in Afghanistan and forms a coalition with ISIS/Taliban/al Qaeda to launch a major attack in America. We tie it back to Iran and decide to finally take them out. We get bogged down in another guerrilla type conflict and after a couple years, Iran nukes our forces in the region, resulting in two or three strategically placed nuclear strikes by America on Iran and the terror cells there.


I could see either of these scenarios being likely.