This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'Maastricht classification of donation after cardiac death.What category is stage 3 ? \nSelect and explain. \nA. Awaiting cardiac arrest, B. Brought in dead, C. Unsuccessful resuscitation, D. Cardiac arrest after brain-stem death', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Non hea beating donors are grouped according to Maastricht classification . REF: WASHINGTONS MANUAL OF CRITICAL CARE', 'role': 'assistant'}]