Which of the following describes a 'Form-Fit' (Formschluss) cargo securing method under VDI 2700?

1. Placing cargo flush against the front bulkhead (Stirnwand), side boards, stanchions, or using locking bars, chocks, and dunnage bags to fill all voids
2. Applying two top-over tie-down straps with ratchets over a slippery steel drum placed in the center of the bed
3. Increasing vehicle tire pressure to reduce trailer bed roll
4. Relying solely on cargo mass to keep heavy items stationary