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: Orthopaedics
Not a deformity of rheumatoid arthritis 
Select and explain. 
A. Swan Neck, B. Boutonnicre, C. Hallux valgus, D. Claw hand
D: Claw hand
Answer: D: Claw hand 
Explanation: None