This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immune system, Subject name: Medicine
Regarding rheumatoid ahritis, all of the following statements are true except- 
Select and explain. 
A. The cricoarytenoid joint may be involved, B. HLA-D4 and HLA-DR4 are positive in patients with seropositive rheumatoid ahritis, C. Subcutaneous nodules are more frequent in seronegative patients, D. Diffuse intestinal fibrosis and pneumonitis may occur
C: Subcutaneous nodules are more frequent in seronegative patients
Answer: C: Subcutaneous nodules are more frequent in seronegative patients 
Explanation: Rheumatoid nodules occur almost exclusively in RF or ACPA positive patients, usually in extensor tendons . Theyare frequently asymptomatic but some may be complicated by ulceration and secondary infection . Ref Davidsons 23e p1023,1024