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 retraction of maxillary anteriors by 1 mm, space required is? \nSelect and explain. \nA. 1 mm, B. 2 mm, C. 0.5 mm, D. 1.5 mm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: For every 1 mm of decrowding, same amount required for alignment.\xa0\nFor every 1 mm of leveling the curve of spee, 0.5 mm space required in the arch.\xa0\nFor every 1 mm of incisor retraction, 2 mm space required.', 'role': 'assistant'}]