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: Pathology
[{'content': 'Thistle-tube appearance of pulp chamber is a feature of: \nSelect and explain. \nA. Coronal dentin dysplasia, B. Regional odontodysplasia, C. Dentinogenesis imperfecta, D. Amelogenesis imperfecta', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]