How does ufsm handle the priority of a set of confict transitions?

[siwifttiger]

The example of conflict transition explains priority of 'parent state' and 'sub state'. Consider this kind of situation:
Simple state A can point to Simple state B by a guard transition AB, Simple state A can also point to Simple state C by a guard transition AC. When AB and AC are satisfied at the same time, which one will be fired first? I know this is beyond semantis of UML.