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 most accepted cause for late incisor crowding is \nSelect and explain. \nA. Late mandibular growth, B. Pressure from third molar, C. Lack of normal attrition, D. Lingual eruption of mandibular incisors', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]