<s>[INST] context: Basic life suppo, more popularly known as CPR, is intended to maintain organ perfusion until definitive interventions can be instituted. The elements of CPR are the maintenance of ventilation of the lungs and compression of the chest. Mouth-to-mouth respiration may be used if no specific rescue equipment is immediately available (e.g., plastic oropharyngeal airways, esophageal obturators, masked Ambu bag). Conventional ventilation techniques during single-responder CPR require that the lungs be inflated twice in succession after every 30 chest compressions. Recent data suggest that interrupting chest compressions to perform mouth-to-mouth respiration may be less effective than a continuous chest compression strategy. Chest compression is based on the assumption that cardiac compression allows the hea to maintain a pump function by sequential filling and emptying of its chambers, with competent valves maintaining forward direction of flow. The palm of one hand is placed over the lower sternum, with the heel of the other resting on the dorsum of the lower hand. The sternum is depressed, with the arms remaining straight, at a rate of approximately100 per minute. Sufficient force is applied to depress thesternum 4-5 cm, and relaxation is abrupt. ref:harrison&;s principles of internal medicine,ed 18,pg no 2247 [/INST] question: In basic life suppo (BLS), suppo is given to which of the following organ- | options: A: Lung B: Hea C: Kidney D: Skeletal muscle | answer: A </s>