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: Radiology
[{'content': 'The region in the crown of a tooth is often mistaken for caries in the intraoral periapical radiograph: \nSelect and explain. \nA. CEJ, B. Dentinoenamel junction, C. Pulp Horn, D. Secondary dentin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]