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': 'Pneumonia results from the proliferation of microbial pathogens at the level of: \nSelect and explain. \nA. Bronchioles, B. Bronchus, C. Interstitium, D. Alveoli', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Pneumonia results from the proliferation of microbial pathogens at the alveolar level. The most common way of access is by aspiration from the oropharynx Rarely, pneumonia occurs hematogenous spread (e.g., from tricuspid endocarditis) or by contiguous extension from an infected pleural or mediastinal space. Ref: Harrison, E-18, P-2131', 'role': 'assistant'}]