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
In polycythaemia vera the most common postoperative complication following major surgery is? 
Select and explain. 
A. Thrombosis, B. Gastric ulcer, C. Diabetes insipidus, D. Haemorrhage
A: Thrombosis
Answer: A: Thrombosis 
Explanation: Ans. is 'a' i.e., Thrombosis