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: Skin
Following are signs of internal malignancy except: 
Select and explain. 
A. Tuberous sclerosis, B. Acanthosis nigricans, C. Clubbing, D. None
D: None
Answer: D: None 
Explanation: D i.e. None