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
Commonest type of bronchogenic carcinoma is 
Select and explain. 
A. Adenocarcinoma, B. Oat cell carcinoma, C. Squamous cell carcinoma, D. Large cell carcinoma
A: Adenocarcinoma
Answer: A: Adenocarcinoma 
Explanation: None