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: Orthopaedics
40 years patient having arthritis of PIP and DIP along with a carpometacarpal joint of the thumb and sparing of the wrist and metacarpophalangeal joint, most likely diagnosis is - 
Select and explain. 
A. Rheumatoid arthritis, B. Osteoarthritis, C. Psoriatic arthritis, D. Pseudogout
B: Osteoarthritis
Answer: B: Osteoarthritis 
Explanation: Involvement of PIP, DIP and 1st Carpometacarpal joint (Carpometacarpal joint of thumb) with sparing of the wrist and the metacarpophalangeal joint is characteristic of OA.