This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': "A 85 year old female developed multiple blisters on trunk and thighs. Nikolsky's sign negative. The lesions came on and off. The most probable diagnosis is NOT RELATED-DERMATOLOGY \nSelect and explain. \nA. Pemphigus vulgaris, B. Bullous pemphigoid, C. Lichen planus, D. Lepra reaction", 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]