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: Medicine
A 35 year old male patient develops involvement of proximal and distal interphalangeal joints and 1st canpo-metacarpal joints with sparing of wrist and metacarophalangeal joint. The Diagnosis is: 
Select and explain. 
A. Osteoahritis, B. Psoriatic ahropathy, C. Rheumatoid ahritis, D. Pseudogout
A: Osteoahritis
Answer: A: Osteoahritis 
Explanation: Answer is A (Osteoahritis)