This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory Failure, Subject name: Medicine
[{'content': 'Most common primary lung cancer in children: \nSelect and explain. \nA. Metastasis, B. Bronchial adenoma, C. Adenocarcinoma, D. Pulmonary blastoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - The most common primary lung tumor is bronchial adenoma. - It includes bronchial carcinoid and adenoid cystic carcinoma. - Metastatic lesions are overall the most common forms of pulmonary malignancy in children.', 'role': 'assistant'}]