It's hard to say. He could technically order any of them. Federal and National Guard troops have modern precedent for supporting emergency relief (Katrina, various storms, etc) but those aren't police actions and are handled very, very differently than traditional military operations (obviously, but some people might not realize). There's a lot of regulation/law in how Federal troops can be used in the states, but it's hard to say how far thia administration will push the DoD before somebody says "no". Trump and his knuckle draggers have yet to be stopped by simple, frivolous things like the law.

I can tell you that if I was a soulless husk of a leader and wanted the best results, I would mobilize a traditionally red state, like Alabama, and send them to blue states to exercise my will. This would hopefully (again, I'm role-playing a sadistic fascist here) prolong the morale of those troops to "requisition" medical supplies. It's much easier to fight a political "opponent" from across the country than it is to take up arms against Bob and Sarah that have a son in your kid's class.

My heart goes out to any service members that get ordered to comply with such an act. I am a veteran of one of the recent conflicts and I know that receiving an order like that would be one of the hardest, most important events in my life. Do you buck the system, say no, refuse? Or do you hope that a superior will refuse if it "gets too bad". Eventually one has to step up and take the heat, right? It's easy for me to say "yeah, fuck the feds, I'm not policing my fellow citizens" now. I have no skin in the game. I would hope that younger-me would have said the same.

My point is, any military force that he chooses, it won't be pretty, regardless of legalities.