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': 'Which of the following malocclusions are more prone to fracture of incisors \nSelect and explain. \nA. Class I Crowding, B. Class II Div. 1, C. Class II Div 2, D. Class III', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]