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: Dental
[{'content': 'All of the following are true about Pemphigus vulgaris except: \nSelect and explain. \nA. Antibodies are present against Dsg-1 and Dsg-3, B. Buccal mucosa is also involved, C. Nikolsky sign negative, D. Histopathology "shows row of tombstone" appearance', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Nikolsky sign is positive in\xa0P.vulgaris, that is lateral pressure on normal skin around active lesions can give rise to new blisters because of extension of seperation between the layers of epidermis.', 'role': 'assistant'}]