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': 'For CD fabrication minimum interarch distance needed? \nSelect and explain. \nA. 8 to 10 mm, B. 18 to 20 mm, C. 28 to 30 mm, D. 36 to 40 mm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]