how to detect collision in unity 2d code example

Example 1: unity 2d collision

void OnCollisionEnter2D(Collision2D col) {
  Debug.Log("Collided with: " + col.gameObject.name);
}

Example 2: collision detector unity c# 2d

void OnCollisionEnter2D(Collision2D coll){)

Example 3: oncollisionenter2d

OnCollisionEnter2D(Collision2D Collider)