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
Stellwag'sign is: 
Select and explain. 
A. Absence of normal winking., B. Failure of convergence of eye balls., C. Exophthalmos., D. None.
A: Absence of normal winking.
Answer: A: Absence of normal winking. 
Explanation: None