In the Aura Component Framework, an infinite loop involving an application event is frequently caused by firing the event from a custom renderer (Option B), specifically from the afterRender or rerender functions.

The framework's rendering lifecycle is sensitive. When a component's state changes, the renderer is invoked to update the DOM. If a developer places code inside a renderer that fires an application event, and that event—or a handler of that event—subsequently modifies an attribute on the same component, the component is marked as "dirty." This triggers the renderer to run again, which fires the event again, creating an infinite loop.

Option A is incorrect because multiple handlers simply result in multiple independent blocks of code executing, not a loop. Option C relates to touch events on mobile but wouldn't cause a loop unless the handler itself re-triggered the event. Option D is incorrect because triggers are server-side and do not directly re-fire client-side application events in a looping fashion. To avoid this, event firing should be restricted to controller or helper actions that are triggered by specific user interactions or discrete system states, rather than the automatic rendering cycle.