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: Microbiology
[{'content': 'Most common cause of community acquired pneumonia - \nSelect and explain. \nA. Strep pneumoniae, B. Kleb pneumoniae, C. Vibrio cholera, D. H. influenzae', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Strep. pneumoniae", 'role': 'assistant'}]