This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rheumatoid Ahritis, Subject name: Medicine
A 45-year-old crane operator at a construction site with pre-existing seropositive rheumatoid ahritis complains of progressive difficulty in breathing. On examination - Rheumatoid nodules are also present. Chest X-ray was performed. What is the diagnosis? 
Select and explain. 
A. Caplan syndrome, B. Felty syndrome, C. Bronchiolitis obliterans organizing pneumonia, D. Lung cancer
A: Caplan syndrome
Answer: A: Caplan syndrome 
Explanation: CXR of this patient is suggestive of - Pneumoconiosis On examination - Rheumatoid nodules are also present. This points to diagnosis of Caplan syndrome. CAPLAN Syndrome: Coal worker pneumoconiosis + Rheumatoid nodules Felty's syndrome- Rheumatoid ahritis with splenomegaly and neutropenia