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
The first step when doing a penumononectomy for cancer of the bronchus is to - 
Select and explain. 
A. Ligate the pulmonary vein, B. Ligate pulmonary artery, C. Divide the bronchus, D. Perform lymphnode clearance
B: Ligate pulmonary artery
Answer: B: Ligate pulmonary artery 
Explanation: • Pneumonectomy is anatomically more straightforward than lobectomy (in carcinoma bronchus):
• The pulmonary artery is first dissected, divided and sutured.
• The pulmonary veins are then isolated, divided and sutured.
• The main bronchus is divided so that no blind stump remains. The technique of stump closure is important if a bronchopleural fistula is to be avoided. The tissues are carefully handled and the stump is usually stapled.