What is a 'Displaced Threshold' (umbral desplazado) on a runway, and what operations are permitted on the portion of the runway preceding the displaced threshold?

1. A threshold located at a point other than the physical beginning of the runway; the preceding paved area (marked with white arrows) is available for takeoff rolls and landing rollout from the opposite direction, but CANNOT be used for landing touchdown.
2. A runway area permanently closed to all aircraft operations.
3. An area available only for helicopter parking.
4. A section where aircraft must taxi at maximum speed.