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': 'Design of the major connector must be determined at the time of: \nSelect and explain. \nA. Primary impression making., B. Treatment planning., C. At the time of the final impression making., D. Any of the above.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Design of the major connector must be determined during diagnostic and treatment planning phase, because mouth preparation procedures depend in part on the contemplated design of major connectors.', 'role': 'assistant'}]