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: Surgery
[{'content': "Stemmer's sign is \nSelect and explain. \nA. Swelling in the foot seen with lymphoedema, B. Loss of normal perimalleolar shape in lymphoedema, C. Subcutaneous fibrosis which makes skin over dorsum of foot not pinchable, D. Pitting Oedema in filariasis", 'role': 'user'}, {'content': "Answer: C \nExplanation: Skin over the dorsum of foot cannot be pinched because of subcutaneous fibrosis in filariasis = STEMMER'S SIGN.", 'role': 'assistant'}]