This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Pathology
[{'content': 'Which blood group is universal donor? \nSelect and explain. \nA. A, B. B, C. O, D. AB', 'role': 'user'}, {'content': 'Answer: C \nExplanation: ANSWER: (C) OREF: Ganong 24th ed page 562Persons with type AB blood are "universal recipients" because they have no circulating agglutinins and can be given blood of any type without developing a transfusion reaction due to ABO incompatibility. Type O individuals are "universal donors" because they lack A and B antigens, and type O blood can be given to anyone without producing a transfusion reaction due to ABO incompatibility. This does not mean, however, that blood should ever be transfused without being cross-matched except in the most extreme emergencies', 'role': 'assistant'}]