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: Dental
[{'content': "All of the following are primary cutaneous disorder except - \nSelect and explain. \nA. Psoriasis, B. Reiter's disease, C. Lichen planus, D. Icthiosis", 'role': 'user'}, {'content': "Answer: B \nExplanation: Reiter's syndrome is primarily a reactive polyarthritis. Cutaneous involvement is a secondary feature.", 'role': 'assistant'}]