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
True about sarcoidosis is- 
Select and explain. 
A. Kveim test in not helpful in diagnosis, B. May be assiciated with positive RA factor, C. Pleural effusion, D. Common is 50 years male
A: Kveim test in not helpful in diagnosis
Answer: A: Kveim test in not helpful in diagnosis 
Explanation: None