This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System Pa 1, Subject name: Physiology
[{'content': 'Neuroendocrine cells in the lungs are: \nSelect and explain. \nA. Dendritic cells, B. Type I pneumocytes, C. Type II pneumocytes, D. APUD cells', 'role': 'user'}, {'content': 'Answer: D \nExplanation: APUD (amine precursor uptake and decarboxylation) cells are neuroendocrine cells found in respiratory system, G.I. tract and other organs; they manufactrure amines (e.g. 5-HT). These cells form carcinoid tumors.', 'role': 'assistant'}]