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': 'Point at which pulp tissue ends and periodontal tissue begins is known as \nSelect and explain. \nA. Accesory canal, B. Cementoenamel junction, C. Cementodentinal junction, D. Dentinoenamel junction', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]