This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'True regarding cardio pulmonary resuscitation is \nSelect and explain. \nA. Most conunon presentation in ECG is asystole, B. Compression to ventilation ratio is 5:1, C. Adrenaline is given if cardioversion fails., D. Calcuim gluconate is given immediately.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]