This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
[{'content': 'This lesion are most commonly seen in which disease? \nSelect and explain. \nA. RA, B. Ankylosing spondylitis, C. Psoriatic Arthritis, D. Gout', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. Psoriatic ArthritisPsoriatic ArthritisIt is a seronegative inflammatory arthritis and associated with characteristic changes in the nails (pitting and transverse ridges).Clinical Featuresa. Asymmetrical oligoarthritis (70%) (DIP involvement is a characteristic feature).b. Sacroiliitis/spondylitis (40%)c. Symmetrical seronegative arthritis (15%)d. Distal interphalangeal joint arthritis (15%)Arthritis mutilans. On X-ray pencil in cup appearance is seen.Hand Joints involved in Psoriasis = PIP+DIP+MCP+ Wrist', 'role': 'assistant'}]