This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Integrated QBank, Subject name: Unknown
[{'content': 'A 1-month-old child presented with bullous lesions at the sites of friction like knees, elbows and fingers. The blisters were hemorrhagic and healed with scarring and milia formation. Nail involvement was seen with sparing of mucosa. Biopsy of the lesion was also taken Which of the following structures is most likely to be involved: - \nSelect and explain. \nA. PA B, B. PA D, C. PA C, D. PA A', 'role': 'user'}, {'content': 'Answer: D \nExplanation: THIS IS A CLASSICAL CASE OF AD EPIDERMOLYSIS BULLOSA DYSTROPHICA. Biopsy reveals a sub-epidermal bulla - suggestive of AD epidermolysis bullosa dystrophica. DISEASE EB SIMPLEX (MOST COMMON) DYSTROPHIC EB JUNCTIONAL EB BLISTERS IN EPIDERMIS IN DERMIS B/W DERMIS AND EPIDERMIS MUTATIONS K 5 OR K 14 COL7A1 LAMA3, LAMB3', 'role': 'assistant'}]