This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Which of the following is the least common site of pain in a case of rheumatoid ahritis? NOT RELATED- OHO 
Select and explain. 
A. Cervical, B. Knee, C. Low back, D. Ankle
C: Low back
Answer: C: Low back 
Explanation: .