This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Grade 1 Lymphedema means \nSelect and explain. \nA. Pitting edema upto the ankle, B. Pitting edema upto knee, C. Non pitiing edema, D. Edema disappearing after overnight rest', 'role': 'user'}, {'content': 'Answer: D \nExplanation: .', 'role': 'assistant'}]