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
Which of the following planes can be examined clinically 
Select and explain. 
A. Frankfort horizontal plane, B. Bolton plane, C. SN plane, D. All of the above
A: Frankfort horizontal plane
Answer: A: Frankfort horizontal plane 
Explanation: None