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': 'Father has a blood group B ; Mother has AB ; Children are not likely to have the following blood group: \nSelect and explain. \nA. O, B. A, C. B, D. AB', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (Blood group O) : There is just no way that children might have blood group 0. The answer is obvious so please excuse me on in explanation to this one.', 'role': 'assistant'}]