When moving a severely injured crash casualty with suspected spinal or pelvic fractures onto a rigid spine board, what is the mandatory technique?

1. Having two people grab the patient's wrists and ankles to swing them like a hammock
2. Dragging the patient by their clothing over the asphalt
3. Rolling the patient down an embankment like a log
4. The 'Log-Roll' technique (轴线翻身法) with 3 to 4 rescuers maintaining the head, shoulders, torso, and pelvis in a single straight rigid axis without any twisting or bending