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: Pathology
[{'content': 'Du Bois sign seen in syphilis is: \nSelect and explain. \nA. Shortening of the little finger, B. Small patches are seen on the back, C. Tightening of the fingers, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: According to the current literature, the term "du Bois sign" characterizes the condition of a shortened fifth finger as a symptom of congenital syphilis.', 'role': 'assistant'}]