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': "The angle's system of classification of malocclusion was modified by: \nSelect and explain. \nA. Simon, B. Dewey's, C. Lischer, D. Ackerman Profit", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]