This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autoimmune skin disorders, Subject name: Dental
[{'content': 'All of the following may lead to plaque formation except \nSelect and explain. \nA. Pityriasis rosea, B. Psoriasis, C. Pemphigus, D. Lichen planus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pemphigus vulgaris is a immunobullous disorder characterised by formation of flaccid blisters in skin and mucous membranes. other options lesions are characterised by papules and plaques. iadvl textbook of dermatology page 1088', 'role': 'assistant'}]