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': 'Nikolsky sign not present in -a) Pemphigusb) Pemphigoidc) Vitiligod) Staphylococcal scalded syndrome \nSelect and explain. \nA. cd, B. bc, C. bd, D. ac', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]