Each nation would have to decide how they would react. I'm pretty sure the US would get additional allies ,so I doubt the Iranians would do this overtly. On the other hand a few floating naval mines of unknown origin would effectively shut down the gulf without a war. That's the most likely method the Iranians would use.
I doubt the Iranians could be stopped from closing the gulf with a short nasty naval engagement. As long as Iran has a coastline, they'll be able to send their little 2 man torpedo boats on suicide missions and fire antiship missiles from their mobile launchers. The US would have to invade and occupy Iran's entire coastline to be effective, which means they'd have to invade and occupy the entire country.
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Let me put this in context for you.
It will be a nasty and short engaement with the Iranians shxt kicked back 20 years. Iran tried to close the straits during the Iran - Iraq War - Oil still moved - they mined the strait - oil still moved.
Fast attack craft are no match for air power. They cannot outrun an air to surface missile.
NATO - and Arab countries will make very short work of the Iranian assets. Will some targets be hit by Iran -Yes. But technology, anti missile systems have improved greatly.
NATO also has a substantial number of advanced cruise missiles. Consider how many are carried on ships of the 5th fleet. Add in the Arab airpower - naval assets etc.
Next - NATO will also target their oil - gas productions - Ports for exports etc. The country will literally be bankrupted without oil. As to Chinese facilities. They will still be targeted. And oil production will not return to normal for years.
NATO will not put troops on the ground. Though they will also go after Iranian Nuke sites. Including their new one buried inside the mountain.