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
Pemphigus vulgaris is characterized by all, except: 
Select and explain. 
A. Positive Nikolsky's sign, B. Oral erosions, C. Subepidermal bulla, D. Tzanck smear showing acantholytic cells
C: Subepidermal bulla
Answer: C: Subepidermal bulla 
Explanation: Pemphigus vulgaris is an intraepidermal blistering disease.