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: Pathology
[{'content': 'Recessive dystrophic epidermolysis Bullosa occurs due to alteration in: \nSelect and explain. \nA. Type 4 collagen, B. Type 6 collagen, C. Type 7 collagen, D. Type 8 collagen', 'role': 'user'}, {'content': 'Answer: C \nExplanation: "Nikolsky\'s sign" is positive in: \n\nPemphigus\nFamilial benign chronic pemphigus (hailey-hailey disease)\nRecessive dystrophic epidermolvsis bullosa [Epidermolysis bullosa occurs due to alteration in structure of type VII \xa0collagen.', 'role': 'assistant'}]