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': 'TMJ has the following: \nSelect and explain. \nA. 2 joint cavities & 1 articular disc., B. 1 joint cavity & 1 articular disc., C. 1 joint cavity & 2 articular disc., D. 2 joint cavities & 2 articular discs.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]