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
Rheumatoid arthritis pericarditis is - 
Select and explain. 
A. Serous, B. Fibrinous, C. Serofibrinous, D. Adhesives
B: Fibrinous
Answer: B: Fibrinous 
Explanation: None