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: Physiology
[{'content': 'Persons having anti-A and anti-B isoagglutinins in their serum belong to which blood group \nSelect and explain. \nA. A, B. B, C. AB, D. O', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]