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': 'Mid point from sella to bolton point is \nSelect and explain. \nA. Registration point, B. Basion, C. Nasion, D. Condylion', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]