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: Dental
[{'content': 'Rarest variety of pemphigus is \nSelect and explain. \nA. Pemphigus vulgaris, B. Pemphigus vegetans, C. Pemphigus foliaceus, D. Pemphigus erythematodes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: .', 'role': 'assistant'}]