You did not give the option that the only things that can be done to provide first aid at the scene of a trauma patient are stopping the bleeding, bandaging, immobilizing, and finally moving the injured person. These four are also known as the four basic techniques of trauma first aid. So, just use the method of elimination for this question.
When encountering an injured or sick person who is bleeding or has a fracture, the rescuer should first remain calm, protect himself, quickly examine the injury, quickly treat the injured or sick person, and call for first aid personnel at the same time. The injured or ambulance personnel in accordance with the following first aid measures to rescue: bleeding techniques - bleeding, especially hemorrhage, belongs to the critical emergency of trauma, if the rescue is not timely, the injured patient will be life-threatening. Hemostasis technology is the first of the first aid technology of trauma.