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': 'The primary function of access openings is to \nSelect and explain. \nA. Facilitate canal medication, B. Provide good access for irrigation, C. Aid in locating canal orifices, D. Provide straight line access to the apex', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]