Final answer:
Option B. The first action when aiding an unconscious soldier is to check for breathing and pulse. CPR should only follow if it's necessary, and you should not elevate legs or offer water before stabilizing the soldier.
Step-by-step explanation:
When you find a soldier who appears to be unconscious and you are not in danger of enemy fire, your first action would be to check for breathing and pulse. This is the primary way to assess the soldier's immediate needs and determine whether they are alive and if there is a necessity for life-saving interventions such as cardiopulmonary resuscitation (CPR). Remember that administering CPR immediately without assessing the situation might be futile or even harmful. Only after confirming that the soldier is not breathing and has no pulse should you proceed with CPR.
During CPR, the position of the heart allows an individual to apply pressure on the sternum to manually compress the blood within the heart, sending it through the systemic and pulmonary circuits. Adhering to current CPR standards is crucial, which includes chest compressions at least 5 cm deep and at a rate of 100 compressions per minute, akin to the rhythm of 'Staying Alive' by the Bee Gees.