Since Aura application events follow the traditional publish-subscribe model, which method is used to fire an event?

`ernit()` is not a standard or recognized method for firing events in the Aura component framework.

`fireEvent()` is not the correct method name for firing events in Aura; the correct method is `fire()`.

When an Aura component needs to broadcast an event, it first obtains an instance of the event using `$A.get('e.namespace:eventName')` and then invokes the `fire()` method on that event instance to publish it, triggering any registered event handlers.

`registerEvent()` is used by a component to declare its ability to fire a specific event, not to actually fire the event itself.