This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory, Subject name: Medicine
Commonest type of lung carcinoma is: 
Select and explain. 
A. Large cell carcinoma, B. Bronchioalveolar carcinoma, C. Squamous cell carcinoma, D. Adeno carcinoma
D: Adeno carcinoma
Answer: D: Adeno carcinoma 
Explanation: (Adenocarcinoma): Ref: 506-H, 1430-CMDT- 09 (551-H17th)Type of Lung carcinomaHarrison'sCMDT* Adeno carcinoma32%35-40%* Bronchioloalveolar3%2%* Squamous cell (Epidermoid)29%25 - 35%* Small cell carcinoma (oat cell)18%15-20%* Large cell carcinoma9%5-10%* "Pop corn " calcification seen in pulmonary hamartoma* Worst prognosis in small cell lung cancers