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
Caplan's syndrome is 
Select and explain. 
A. Splenomegaly + Neutropenia, B. Rheumatoid Arthritis + Pneumoconiosis, C. Pneumoconiosis + Splenomegaly, D. Pneumoconiosis + Neutropenia
B: Rheumatoid Arthritis + Pneumoconiosis
Answer: B: Rheumatoid Arthritis + Pneumoconiosis 
Explanation: Rheumatoid Arthritis + Pneumoconiosis nodules = Caplan's syndrome.
Neutropenia + Splenomegaly + Nodular RA = Felty's syndrome.