This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'The most common causative organism causing lobar pneumonia is \nSelect and explain. \nA. Staphylococcus aureus, B. Streptococcus pyogenes, C. Streptococcus pneumonia, D. Hemophilus influenza', 'role': 'user'}, {'content': "Answer: C \nExplanation: Although Streptococcus pneumoniae is most common, other organisms must also be considered in light of the patient&;s risk factors and severity of illness.(Ref: Harrison's 18/e p2131)", 'role': 'assistant'}]