In Unity, when is the "OnTriggerEnter" method executed?

The "OnTriggerEnter" method is executed when another collider, specifically a GameObject with a Collider component marked as a trigger, enters the trigger collider's bounds. This method allows developers to detect interactions between objects, such as characters entering specific zones, picking items, or triggering events when certain conditions are met. The ability to respond to collisions only when an object enters a designated trigger area is essential for implementing various gameplay mechanics, such as checkpoints or power-up pickups.

In Unity, this method is part of the MonoBehaviour class and works closely with the physics engine, enabling collision detection and management of overlapping physics entities. Thus, option C accurately describes the event that invokes the "OnTriggerEnter" method in Unity.