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: Ophthalmology
[{'content': "Stellwagg's sign of graves disease is \nSelect and explain. \nA. Difficulty in eversion of upper lid, B. Infrequent blinking, C. Fullness of eyelids, D. Lid lag", 'role': 'user'}, {'content': "Answer: B \nExplanation: Lid lag - Von graefe's sign.\nFullness of eyelids - Enroth's sign.", 'role': 'assistant'}]