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: Dental
[{'content': "According to the Kennedy's classification the posterior unilateral edentulous space is: \nSelect and explain. \nA. Class I situation, B. Class II situation, C. Class III situation, D. None of the above", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]