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': 'As a general rule in borderline crowding cases of a broad facial type: \nSelect and explain. \nA. An expansion treatment should be carried out, B. Extraction therapy, should be considered, C. No treatment required, D. Only surgical treatment required', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Key comment:\nIn broad face type(brachycephalic) patient with mild crowding, if expansion is possible, it is the first line of treatment of choice rather than extraction.', 'role': 'assistant'}]