This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal system, Subject name: Anatomy
[{'content': 'Which of the following is true about psoriatic ahritis \nSelect and explain. \nA. Involves distal joints of hand and foot, B. Pencil in cup deformity, C. Sacroiliitis, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Reference Robbins page no Pg 8th 1241', 'role': 'assistant'}]