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
Involvement of PIP jt, DIP jt and the carpo-mcp jt of base of thumb with sparing the wrist is seen in: 
Select and explain. 
A. Rheumatoid ahritis, B. Osteoahritis, C. Psoriatic ahritis, D. Pseudogout
B: Osteoahritis
Answer: B: Osteoahritis 
Explanation: Sparing of wrist and metacarpophalangeal joints, with involvement of base of thumb is characteristic of osteoahritis. Ref: Osteoahritis: Diagnosis And Medical/Surgical Management By Roland W. Moskowitz, 2007 ; Harrison's Internal Medicine, 14th Edition, Pages 300, 1885, 1938 and 15th Edition, Page 1985