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
Post-auricular ecchymosis in cases of fracture of the base of the skull is called: 
Select and explain. 
A. Battle's sign, B. Tinel's sign, C. Trousseau's sign, D. Nikolsky's sign
A: Battle's sign
Answer: A: Battle's sign 
Explanation: None