Final answer:
The first action for a first responder arriving at an emergency scene is to survey the scene for potential safety hazards (option A). Once the scene is deemed safe, they can access the patient and initiate appropriate care. Determining the number of patients involved is also important.
Step-by-step explanation:
The correct first action for a first responder arriving at an emergency scene is to A. Survey the scene for potential safety hazards. This step is crucial to ensure the safety of the first responder and any other potential victims. By assessing the scene and identifying hazards such as fire, smoke, or unstable structures, the first responder can take appropriate measures to protect themselves and others.
Once the scene has been surveyed and deemed safe, the first responder can proceed to B. Access the patient and initiate the appropriate care. This may involve providing first aid, cardiopulmonary resuscitation (CPR), or other appropriate medical interventions depending on the condition of the patient.
Determining the exact number of patients involved, as stated in option D, is also important. However, it is not the first action that should be taken. Once the immediate safety of the scene has been ensured and care has been initiated for the accessible patient, the first responder can assess the situation further to determine the number of patients and the additional resources needed.