This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal infections, Subject name: Anatomy
[{'content': 'Osteomyelitis of spine is caused by most common organism ? \nSelect and explain. \nA. Staphylococcus aureus, B. Pseudomonas, C. Tuberculosis, D. Streptococcus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Staphylococcus aureus , overall , worldwide staph. aureus is the commonest organism. in India tuberculosis is the commonest. ref : maheswari 9th ed', 'role': 'assistant'}]