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: Gynaecology & Obstetrics
A 40-year old man presented with acute onset pain and swelling of left great toe. On X-ray, punched out lytic lesion seen on phalanx with sclerotic margins and overhanging bony edges. Diagnosis is: 
Select and explain. 
A. Gout, B. Rheumatoid ahritis, C. Psoriatic ahritis, D. Reiter's syndrome
A: Gout
Answer: A: Gout 
Explanation: Ans. a. Gout