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 cementoenamel junction is approximately at the level at which the root canal becomes \nSelect and explain. \nA. Twisted, B. Curved, C. Pulp chamber, D. Lateral canal', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]