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 three fourth crown is contraindicated in \nSelect and explain. \nA. Anterior teeth with short clinical crown, B. Abraded proximal region, C. Abraded lingual region, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]