This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Ahritis involving DIP, PIP, 1st carpometacarpal with sparing of MCP and wrist joints is typical of ? 
Select and explain. 
A. Osteoahritis, B. Rheumatoid ahritis, C. Ankylosing spondylitis, D. Psoriatic ahritis
A: Osteoahritis
Answer: A: Osteoahritis 
Explanation: Ans. is 'a' i.e., Osteoahritis