This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Anatomy
[{'content': 'Most common primary bronchogenic carcinoma is \nSelect and explain. \nA. Small cell carcinoma, B. Squamous cell carcinoma, C. Mixed cell carcinoma, D. Adenocarcinoma', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Histological type . Frequency Adenocarcinoma . 32% Squamous cell carcinoma . 29% Small cell carcinoma . 18% Large cell carcinoma. 9% Carcinoid. 1% Ref Harrison 19th edition pg 2584', 'role': 'assistant'}]