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: Medicine
[{'content': 'True about sarcoidosis is- \nSelect and explain. \nA. Kveim test in not helpful in diagnosis, B. May be assiciated with positive RA factor, C. Pleural effusion, D. Common is 50 years male', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]