This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lower Limb Traumatology, Subject name: Orthopaedics
[{'content': 'Unna boot is used for treatment of: \nSelect and explain. \nA. Diabetic foot ulcer, B. Varicose ulcers, C. Ankle instability, D. Calcaneum fracture', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Unna boot is used for the varicose vein ulcers.', 'role': 'assistant'}]