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
[{'content': 'Lung to lung metastasis is seen in \nSelect and explain. \nA. Adenocarcinoma of lung, B. Squamous cell carcinoma, C. Small cell carcinoma, D. Neuroendocrine tumor of lung', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]