This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oncology, 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: Pulmonary metastasis from primary lung cancer and its treatment. On admission, pulmonary metastases were radiographically found in 44 of 529 patients with adenocarcinoma (8.3%), 8 of 427 patients with squamous cell carcinoma (1.9%) and 2 of 150 patients with small cell carcinoma (1.3%) Ref Harrison 20th edition pg 559', 'role': 'assistant'}]