"What does that mean 'which court'? What are the choices?"
State or Federal court, I imagine. This is really a state court issue, since disputes regarding contract law are state actions. But since the losses exceed $75,000, then it could be filed in Federal Court.
Of course, they could try and request the injunction from a non-Manhattan-based state court. Perhaps that is what they mean.
A Manhattan judge this afternoon granted an injunction filed by the producers of “How the Grinch Stole Christmas” that will allow the production to reopen despite the stagehands strike.