This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal System, Subject name: Radiology
[{'content': "Dot-Dash appearance is a feature of? \nSelect and explain. \nA. Rheumatoid arthritis, B. Psoriatic arthritis, C. Reiter's syndrome, D. Osteoarthritis", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans AThis appearance is classically described in rheumatoid arthritis. It refers to focal loss of continuity of the subchondral bone. It is seen in the radial heads of the second and third metacarpals in the hand and medial aspect of the heads of the first metatarsal and lateral aspect of the fifth metatarsal in the feet', 'role': 'assistant'}]