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: Orthopaedics
[{'content': 'Involvement of the joints of hand is relatively uncommon in which of following ahritis? \nSelect and explain. \nA. Ankylosing spondylitis, B. Reactive ahritis, C. Psoriatic ahritis, D. Rheumatoid ahritis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Joints involved in ankylosing spondylitisAnkylosing spondylitis primarily affects the axial skeletonThe disease usually begins in the sacroiliac joints and usually extends upwards to involve the lumbar, thoracic, and often cervical spineIn the worst cases, the hips or shoulders are also affected. The hip joint is the most commonly affected peripheral jointRarely knee and ankle are also involved(Refer: Mohindra's Fundamentals of Ohopedics, 2nd edition, pg no. 302, 426)", 'role': 'assistant'}]