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: Orthopaedics
[{'content': 'Acute Osteomyelitis is most commonly caused by - \nSelect and explain. \nA. Staphylococcus aureus, B. Actinomyces bovis, C. Nocardia asteroids, D. Borrelia vincentii', 'role': 'user'}, {'content': 'Answer: A \nExplanation: It is caused most commonly by staphylococcus aureus.', 'role': 'assistant'}]