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': 'Which of the following planes can be examined clinically \nSelect and explain. \nA. Frankfort horizontal plane, B. Bolton plane, C. SN plane, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]